- Nice, Provence-Alpes-Côte d'Azur, France
Philippe AUDRA
University of Nice, Polytech Nice-Sophia, Faculty Member
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Research Interests: Geography and New Guinea
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The Camou springs (Arbailles Massif, French Western Pyrenees) display an unusual close association of a typically cold karstic spring that drains the Urgonian western limb of the Arbailles, and a thermo-mineral spring (33.5°C; salinity... more
The Camou springs (Arbailles Massif, French Western Pyrenees) display an unusual close association of a typically cold karstic spring that drains the Urgonian western limb of the Arbailles, and a thermo-mineral spring (33.5°C; salinity 17.7 g/L). The latter gains its mineralization at the contact of Triassic evaporites mainly through a deep loop in the Apanicé syncline. The fast upflow of this deep water occurs at the cross of large active lines (the North-Pyrenean thrust located at depth, and the Saison transverse fault). Cave diving in the nearby Maddalen Cave allowed reaching the phreatic passage at the origin of the cold spring, which however also crosses the thermal body in the third sump (S3). Both water bodies are separated by a sharp thermocline. 6 pressure-temperature dataloggers were placed in both water bodies along the thermocline for 6 months. The dataloggers located downstream on either side of the thermocline show at the beginning of flood first a rise of the thermal ...
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Alteration of conventional carbonate stable isotopes (δ18O, δ13C) in cave walls has been shown to be a useful tool to identify cave formation driven by deep-seated processes, i.e., hypogene karstification. If combined with a prior... more
Alteration of conventional carbonate stable isotopes (δ18O, δ13C) in cave walls has been shown to be a useful tool to identify cave formation driven by deep-seated processes, i.e., hypogene karstification. If combined with a prior information on the paleowater stable isotope composition, further insights can be obtained on the temperature and the source of the paleowater. Clumped isotope composition (Δ47) of carbonates is an independent measurement of temperature, and if combined with the conventional stable isotopes, can provide information on the paleowater stable isotope composition. On the example of Provalata Cave (N. Macedonia), we apply for the first time, both conventional and clumped stable isotope analysis, and identify two different isotope alteration trends, reflecting two distinct hydrothermal events: an older, hotter one, where isotope alteration was likely related to isotope diffusion, lowering the δ18O values of the carbonate; and a younger one, related to the cave f...
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Research Interests: Geology, Geochemistry, Geophysics, Carbonate, Lithology, and 3 moreKarst, Chalcedony, and Dolomitization
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L’Association francaise de karstologie est presentee a travers son organisation, sa vie administrative et ses activites. Celles-ci sont essentiellement l’activite editoriale, l’organisation de rencontres annuelles de terrain et de... more
L’Association francaise de karstologie est presentee a travers son organisation, sa vie administrative et ses activites. Celles-ci sont essentiellement l’activite editoriale, l’organisation de rencontres annuelles de terrain et de colloques. Apres quarante annees d’existence, l'association a organise 43 excursions de terrain (dont 13 a l’etranger), edite plus de 70 numeros de Karstologia (soit plus de 400 articles sur plus de 4 700 pages) et 20 numeros de Karstologia memoires. Sachant que l’association ne depasse pas la centaine de membres, ce bilan peut etre considere comme positif.
Research Interests: Humanities and Art
L'impact meconnu des chauves-souris et du guano dans l'evolution morphologique tardive des cavernes : Les chauves-souris sont considerees comme des occupants emblematiques des grottes. Les colonies, parfois de taille gigantesque,... more
L'impact meconnu des chauves-souris et du guano dans l'evolution morphologique tardive des cavernes : Les chauves-souris sont considerees comme des occupants emblematiques des grottes. Les colonies, parfois de taille gigantesque, peuvent occuper les cavernes sur de tres longues periodes. Ainsi, il se constitue des accumulations de guano dont le volume a favorise l'exploitation des phosphates, a l'echelle artisanale voire industrielle. L'impact des chauves-souris est triple : leur respiration degage du CO 2 , leur urine est corrosive, et la mineralisation du guano libere des acides (carbonique, nitrique, sulfurique, phosphorique). Ces substances agressives agissent sur la roche et les concretions carbonatees, soit par corrosion directe du sol encaissant au contact du guano, soit par condensation-corrosion sur les parois et les plafonds. Bien que tardif dans l'histoire des cavites, l'impact speleogenetique sur les parois est considerable et peut aller jusqu...
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Grotte de Saint-Marcel: a major French cave system for Speleology, Sciences, Tourism and Education Located in Ardeche (South east of France), grotte de Saint-Marcel is actually a 56 km long cave system with more than 18 km explored by... more
Grotte de Saint-Marcel: a major French cave system for Speleology, Sciences, Tourism and Education Located in Ardeche (South east of France), grotte de Saint-Marcel is actually a 56 km long cave system with more than 18 km explored by cave diving. The cave, was discovered by the locals on 1835, the cave explorations started a few years later. On 1894, Martel published the first results in “Les Abimes”. The Municipality decided on 1870, to organize a tour in the galleries closed to the entrance, the tourists came by boat on the river Ardeche. From the 60’s, different caving clubs are involved in the systematic exploration of this huge cave system. During the same period, the construction of the touristic road, on 1962, through the gorges, has increased the tourism activity in the cave. On 1988, a territorial program for cave and karst protection put in place, and a natural reserve: “Reserve des gorges de l’Ardeche” was created for a sustainable management of the nature protection and...
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Abstract Caves developed in carbonate units have a significant role in fluid flow, but most of these subsurface voids are below seismic resolution. We concentrated our study on four caves to determine the roles of fractures and folds in... more
Abstract Caves developed in carbonate units have a significant role in fluid flow, but most of these subsurface voids are below seismic resolution. We concentrated our study on four caves to determine the roles of fractures and folds in the development of karst conduits that may form flow pathways in carbonate reservoirs. We performed structural field investigations, petrographic analyses, and geometric characterization using Light Detection and Ranging (LIDAR) for caves in Neoproterozoic carbonates of the Salitre Formation, central part of the Sao Francisco Craton, Brazil. We found that the conduit shape, usually with an ellipsoidal cross-section, reflects the tectonic features and textural variations. Carbonate layers containing pyrite and low detritic mineral contents are generally karstified and appear to act as favorable flow pathways. Our results indicate that the development of the karst system is related to fracture corridors formed along parallel and orthogonal sets of fold hinges, which provide preferential pathways for fluid flow and contribute to the development of super-K zones. This study provides insights into the prediction of subseismic-scale voids in carbonate reservoirs, with direct application for the hydrocarbon and hydrogeology flow and storage.
Research Interests: Geology, Hydrogeology, Structural Geology, Cave, Carbonate, and 3 moreKarst, Carbonate Rock, and Hinge
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Research Interests: Geology, Corrosion, Pleistocene, Cave, Phreatic, and 7 moreGypsum, Calcite, Guano, Arid, East Mediterranean, Efflorescence, and Condensation–corrosion
Serpents Cave, located in the French Alps, contains a sulfidic-thermal (41 uC) karst spring. Degassing of the sulfidic vapor produces diverse sulfate minerals. The reaction with the limestone host-rock produces gypsum, anhydrite, sulfur,... more
Serpents Cave, located in the French Alps, contains a sulfidic-thermal (41 uC) karst spring. Degassing of the sulfidic vapor produces diverse sulfate minerals. The reaction with the limestone host-rock produces gypsum, anhydrite, sulfur, and magnesium calcite. The reaction with an artificial material (aluminum door) produces alunogen, tschermigite, and jurbanite. Microbial activity is suspected in the genesis of sulfur and tschermigite. Aluminum sulfates have usually been reported in mines, in volcanic settings, and in rock-shelters in phyllites. Some of these alum minerals such as tschermigite are rarely observed in caves, and jurbanite is identified here for the first time in a cave. Serpents Cave is therefore an important site for sulfate minerals in caves, even if the aluminum sulfates should be considered border minerals because they originate from sulfur vapor reaction with artificial media.
Research Interests: Geology, Geochemistry, Cave, Cave and Karst Studies, Karst, and 6 moreSulfate, Gypsum, Calcite, Chalcedony, Mineral, and anhydrite
Research Interests: Geology, Paleontology, Cave, Speleogenesis, Cretaceous, and 5 moreKarst, Neogene, Breccia, Iron ore, and Hypogenic Caves
ABSTRACT Sulfuric acid caves can display a variety of forms, from 3D maze systems, to isolated chambers, and more or less maze-like water table caves. Most of the voids are normally generated at or immediately above the water table, where... more
ABSTRACT Sulfuric acid caves can display a variety of forms, from 3D maze systems, to isolated chambers, and more or less maze-like water table caves. Most of the voids are normally generated at or immediately above the water table, where condensation-corrosion processes are dominant, creating a set of characteristic meso- and micromorphologies. This paper deals with the description of four very typical sulfuric acid water table caves: the Grotte du Chat in Provence (France), the Acqua Fitusa Cave in Sicily (Italy), and the Bad Deutsch Altenburg and Kraushöhle caves in Austria.
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Thanks to its immunity, karst is an excellent recorder of environmental change, which also offers the possibility for dating. Karst records position of old base levels, in particular to which were linked horizontal underground drains... more
Thanks to its immunity, karst is an excellent recorder of environmental change, which also offers the possibility for dating. Karst records position of old base levels, in particular to which were linked horizontal underground drains located near the piezometric surface. After a base level lowering, a new drain appears at a lower level, the old perched drain being abandoned. If base level lowering is slow, the initial drain is progressively entrenched, forming a canyon. The "Combe Rajeau" cave system corresponds to this last type: a 100 m high underground canyon, continuously entrenched during the Ardeche valley downcutting. The underground river left several terraces during the entrenchment. Knowing that speleothem U/Th radiometric dating method covers only the most recent part of karst systems history, which spans over several million years, paleomagnetism has been applied to date the Combe Rajeau sediments. A more precise knowledge of the evolution phases of this system...
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HAL - hal.archives-ouvertes.fr, CCSd - Centre pour la Communication Scientifique Direct. Accueil; Dépôt: S'authentifier; S'inscrire. Consultation: Par domaine; Les 30 derniers dépôts; Par année de publication, rédaction, dépôt;... more
HAL - hal.archives-ouvertes.fr, CCSd - Centre pour la Communication Scientifique Direct. Accueil; Dépôt: S'authentifier; S'inscrire. Consultation: Par domaine; Les 30 derniers dépôts; Par année de publication, rédaction, dépôt; Par type de publication; ...
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The decay of bat guano deposits in caves produces mineral accumulations, mainly phosphates and secondary sulfates. Chameau Cave, Eastern Morocco, is located in the semi-arid Bni Snassen Mountains. It is composed of semi-active and dry... more
The decay of bat guano deposits in caves produces mineral accumulations, mainly phosphates and secondary sulfates. Chameau Cave, Eastern Morocco, is located in the semi-arid Bni Snassen Mountains. It is composed of semi-active and dry passages, and is featured by strong condensation-corrosion on the walls, presence of fluvial sediments, and old corroded flowstones. Due to forced and convective airflow, the cave is generally very dry, with some damp sites related to condensation. Samples collected on the surface of different passages and along two sediment profiles yielded minerals related to bat guano decay. On recent or fresh guano, precursor minerals correspond to sulfate (gypsum), phosphate-sulfate (ardealite) and phosphate (brushite). Phosphates (hydroxylapatite, fluorapatite) occur at the interface with host rock or carbonate speleothems. At the contact of phyllosilicates contained in allogenic fluvial deposits or shale partings, or with pyrite-rich sediments, various phosphate...
Research Interests: Earth Sciences, Geology, Geochemistry, Mineralogy, Weathering, and 7 moreSpeleology, Cave, Mineral Physics, Pyrite, Guano, Phosphates, and Sulfates
Audra Philippe. Le karst de Divaca (Slovénie), Par Andrej Mihevc, 2001. In: Karstologia : revue de karstologie et de spéléologie physique, n°37, 1er semestre 2001. Grottes et capture de la Moselle et Glaces souterraines et climat. pp. 60-61
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Several sinkhole collapses were occurred in the many sites in urban areas and/or their rural periphery; in NE Algeria, in the last few years. The abrupt collapse causes damages to properties, infra-structures, and even lives. The most... more
Several sinkhole collapses were occurred in the many sites in urban areas and/or their rural periphery; in NE Algeria, in the last few years. The abrupt collapse causes damages to properties, infra-structures, and even lives. The most spectacular oneoccurred in February 2009 inside the Cheria city, Northwest of Tebessa department, with a diameter of more than a hundred meters. This abrupt collapse is due to a sudden rupture of the roof of a large underground karst cavity. It caused panic-stricken among the population living near the crater. In order to investigate the origin of this phenomenon, we combine several geophysical and geotechnical methods, such as Ground Penetrating Radar, Electrical Resistivity Tomography, Standard Penetration Test, Mechanical Drill Core, Cave Survey Photogrammetry, etc. It appears that each method may provide specific information. Their comparison allows to precise the results itself, the limits and the application field of each. Consequently a number o...
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Audra Philippe. Les conditions d'écoulement des plateaux calcaires de l'Est de la France, par Alain Devos, 2010. In: Karstologia : revue de karstologie et de spéléologie physique, n°57, 1er semestre 2011. Spéléothèmes du Désert... more
Audra Philippe. Les conditions d'écoulement des plateaux calcaires de l'Est de la France, par Alain Devos, 2010. In: Karstologia : revue de karstologie et de spéléologie physique, n°57, 1er semestre 2011. Spéléothèmes du Désert libyque (Egypte) et Fantômes de roche en Entre-deux-Mers (Gironde) pp. 61-62
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Audra Philippe. "Evolution of karst : from prekarst to cessation". Postojna, septembre 2002, Organisé par l'Institut de recherche du Karst de Postojna (IZRK), Slovénie, sous la responsabilité de Fr. Gabrovšek. In:... more
Audra Philippe. "Evolution of karst : from prekarst to cessation". Postojna, septembre 2002, Organisé par l'Institut de recherche du Karst de Postojna (IZRK), Slovénie, sous la responsabilité de Fr. Gabrovšek. In: Karstologia : revue de karstologie et de spéléologie physique, n°41, 1er semestre 2003. Traçage sous les Dents du Midi (Valais) et Observations morphologiques dans l'abîme de Maramoye (Var) p. 56
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This chapter focuses on a dam break assumptions and assesses a flood risk in the downstream area of the Eg hydropower plant, Mongolia. Two-dimensional DHI-MIKE model was set up. The model presents the volume of water in a reservoir, a... more
This chapter focuses on a dam break assumptions and assesses a flood risk in the downstream area of the Eg hydropower plant, Mongolia. Two-dimensional DHI-MIKE model was set up. The model presents the volume of water in a reservoir, a flood mapping, and flood risk zone in the downstream area of the hydropower station. The model has been supplied by the Eg-Hantai, Selenge-Khutag, and Selenge-Khylganat hydrological stations data from 1994 to 2006, which are a water level, inflow discharge, and precipitation, and it has been collected by the Mongolian Institute of Meteorology Hydrology and Environment. Terrain property of objects in schematic outline was determined on a digital elevation model (DEM), the elevation data were produced by digitizing topographic maps. The dam break has been simulated with Mike21 modeling software. The initial elevation is 887.8 m (water depth 59 m) at the reservoir. Before dam failure, the observed discharge and the simulated Mike21 model’s outflow were an...
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Audra Philippe. Cave and Karst Science 2005 vol. 32, n° 2-3 (n° spécial Tiankengs). In: Karstologia : revue de karstologie et de spéléologie physique, n°50, 2e semestre 2007. Suivi climatique dans la grotte de Lascaux. pp. 63-64
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Audra Philippe. Les risques naturels en montagne Liliane Besson, 1996. In: Karstologia : revue de karstologie et de spéléologie physique, n°28, 2e semestre 1996. Les «Forêts de Pierre» de Lunan (Chine) pp. 62-63
Audra Philippe. Annotated bibliography of karst publications, 2001, N° 9 Suppl. Acta Carsologica, vol. 30, Edité par A. Kranjc. In: Karstologia : revue de karstologie et de spéléologie physique, n°39, 1er semestre 2002. Fantôme de roche... more
Audra Philippe. Annotated bibliography of karst publications, 2001, N° 9 Suppl. Acta Carsologica, vol. 30, Edité par A. Kranjc. In: Karstologia : revue de karstologie et de spéléologie physique, n°39, 1er semestre 2002. Fantôme de roche (Belgique) et Relations glacier-karst (Jura méridional) p. 62
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Nouvelles considerations sur la genèse des cavités dans les Alpes depuis le Miocène. Les progrès dans la compréhension des processus spéléogénétiques ainsi que les recherches intensives conduites dans les Alpes depuis quelques décennies... more
Nouvelles considerations sur la genèse des cavités dans les Alpes depuis le Miocène. Les progrès dans la compréhension des processus spéléogénétiques ainsi que les recherches intensives conduites dans les Alpes depuis quelques décennies donnent de nouvelles ...
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Research Interests: Geology, Desert Ecology, Speleology, Cave, United Arab Emirates, and 8 moreGE, QE, Mineral Physics, Urea, Bat Guano, Arid, Cave Minerals, and Allantoin
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Vengono presentati i risultati preliminari di uno studio condotto su alcune grotte ipogeniche della Sicilia, ritenute fino a questo momento di natura epigenica: il sistema carsico di Monte Inici e la Grotta dell\u2019Acqua Fitusa. Il... more
Vengono presentati i risultati preliminari di uno studio condotto su alcune grotte ipogeniche della Sicilia, ritenute fino a questo momento di natura epigenica: il sistema carsico di Monte Inici e la Grotta dell\u2019Acqua Fitusa. Il primo sistema \ue8 localizzato nella Sicilia nordoccidentale lungo il versante sudorientale di Monte Inici. \uc8 costituito da due cavit\ue0, la Grotta dell\u2019Eremita e l\u2019Abisso dei Cocci, che si sviluppano in calcari e calcari dolomitici della Fm. Inici (Giura inf.) e in calcari ad ammoniti della Fm. Buccheri (Giura medio-sup.). Si tratta di sistemi tridimensionali freatici che raggiungono una lunghezza di oltre 2km e una profondit\ue0 superiore a 300m. Sono caratterizzati da diversi livelli di gallerie, spesso impostate lungo piani di strato, connesse da profondi pozzi che seguono sistemi di fratture subverticali o piani di faglia. Lungo le pareti e il soffitto degli ambienti ipogei sono state riconosciute numerose morfologie legate a processi di condensazione-corrosione, quali megascallops e cupole di diverse dimensioni. I depositi chimici consistono di speleotemi carbonatici, croste di gesso, aghi di aragonite, croste di carbonato-apatite e altre mineralizzazioni in fase di analisi. Entrambe le grotte sono prive di sedimenti di natura alluvionale. L\u2019intero sistema \ue8 verosimilmente connesso alla risalita di acque termali sulfuree che attualmente emergono a Est e a quota inferiore rispetto alle cavit\ue0. L\u2019evoluzione e l\u2019ampliamento dei vuoti carsici sembrano inoltre essere legati a flussi d\u2019aria che favoriscono processi di corrosione per condensazione. La Grotta dell\u2019Acqua Fitusa \ue8 localizzata nella Sicilia centrale, lungo la scarpata nordorientale del rilievo La Montagnola. La grotta si sviluppa su almeno tre livelli di gallerie per circa 700m raggiungendo una profondit\ue0 di 25m, lungo brecce carbonatiche a rudiste, risedimentate, della Fm. Crisanti (Creta sup.). Si tratta di una grotta sulfurica epifreatica inattiva, formatasi in corrispondenza della superficie piezometrica. Attualmente la sorgente di acqua sulfurea (T=25\ub0C) \ue8 ubicata a circa 300m a nordovest e ad una quota inferiore rispetto alla cavit\ue0. La grotta \ue8 caratterizzata da numerose forme originate da processi di corrosione per condensazione, quali: cupole, nicchie parietali a diversa quota, megascallops, boxwork, canali di condensazione lungo il soffitto, ecc. Nicchie di sostituzione connesse a processi di corrosione-sostituzione sono presenti in molti ambienti della grotta. Intagli a tetto piatto, dovuti a corrosione laterale da parte della tavola d\u2019acqua termale, incidono le pareti della grotta a diversa altitudine, registrando antiche fasi di abbassamento del livello di base dell\u2019erosione. Cristalli e croste di gesso, gesso massivo sono diffusi. L\u2019origine della cavit\ue0 \ue8 legata a fenomeni di corrosione della roccia carbonatica con sostituzione di gesso da parte delle acque sulfuree termali. In particolare, l\u2019allargamento dei vuoti e la genesi delle principali forme sono legati al degassamento di H2S nell\u2019atmosfera grotta, ossidazione dei solfuri e convezione termale che produce intensi processi di corrosione per condensazione al di sopra della superficie piezometrica
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Aix-les-Bains (Savoie, France) owes its name and reputation to the thermal springs that occur along the eastern shore of Lake Bourget, France largest natural lake. Although the city waters have been exploited since Antiquity, scientific... more
Aix-les-Bains (Savoie, France) owes its name and reputation to the thermal springs that occur along the eastern shore of Lake Bourget, France largest natural lake. Although the city waters have been exploited since Antiquity, scientific investigations into the nature and characteristics of the hydrothermal karst from which they emerge did not begin until the early 19th century. The present article traces the history of these investigations and summarizes the results of more than two centuries of scientific research. Today, the only visible signs of karstification related to hydrothermal flows are to be found in the discharge zone in the Urgonian limestone anticline that rises above the city centre. These features are: – the Grotte des Serpents, which houses the Alun Spring, the system main natural discharge, – the Chevalley Aven, a blind chimney that was accidentally uncovered in 1996, – other hydrothermal springs that are too small to enter, including the Soufre Spring. Although sc...
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... CAVE, FRANCE PHILIPPE AUDRA1 AND FABIEN HOBLE´ A2 ... Chevalley Aven is a blind chimney developed above the water table, made of stacked spheres arranged in a bush-like pattern, originating mainly from condensation-corrosion (Audra et... more
... CAVE, FRANCE PHILIPPE AUDRA1 AND FABIEN HOBLE´ A2 ... Chevalley Aven is a blind chimney developed above the water table, made of stacked spheres arranged in a bush-like pattern, originating mainly from condensation-corrosion (Audra et al., 2007). ...