Archaeomorphological Mapping: Rock Art and the Architecture of Place.

Understanding the rock art of a cave or rock shelter requires positioning the art in its landscape setting. This involves both spatial and temporal dimensions because a site’s layout changes through time, necessitating an examination of site formation processes. In this chapter, the authors present a new approach—archaeomorphology—that unites archaeological and geomorphological methods to explore the history of the objects and spaces that make up a site. Archaeomorphological mapping allows researchers to track through time the changing configuration of sites, including rock surfaces, the morphogenic forces at work, and, with this, the changing spatial contexts of the art on its surfaces. Archaeomorphology shifts attention away from the site as a ‘natural’ canvas upon which inscriptions were made to its social engagement as an actively constructed architectural and performative space

Detection and localization of a Ca2+-ATPase activity in Toxoplasma gondii.

Toxoplasma gondii, the agent causing toxoplasmosis, is an obligate intracellular protozoan parasite. A calcium signal appears to be essential for intracellular transduction during the active process of host cell invasion. We have looked for a Ca2+-transport ATPase in tachyzoites and found Ca2+-ATPase activity (11-22 nmol Pi liberated/mg protein/min) in the tachyzoite membrane fraction. This ATP-dependent activity was stimulated by Ca2+ and Mg2+ ions and by calmodulin, and was inhibited by pump inhibitors (sodium orthovanadate or thapsigargin). We used cytochemistry and X-ray microanalysis of cerium phosphate precipitates and immunolabelling to find the Ca2+, Mg2+-ATPase. It was located mainly in the membrane complex, the conoid, nucleus, secretory organelles (rhoptries, dense granules) and in vesicles with a high calcium concentration. Thus, Toxoplasma gondii possesses Ca2+-pump ATPase (Ca2+, Mg2+-ATPase) as do eukaryotic cells

Le karst subpolaire de Madre de Dios (Magallanes, Patagonie chilienne) : un chef-d'oeuvre du géopatrimoine mondial

International audienceLocated at 50° South in Chilean Patagonia, explored by the association Centre Terre since 2000, Madre de Dios archipelago is one of the southernmost karst regions on Earth. Bordered by the Pacific Ocean to the west, Madre de Dios is exposed to subpolar oceanic conditions with extreme precipitation rates (8 to 12 m/year) and strong westerly winds. The archipelago is comprised of sedimentary (including limestone) and plutonic rocks. The speleogenesis interacted with successive glaciations and associated sea-level variations. This set of conditions induces the development of a binary karst characterized by record dissoultion rates and very specific landforms, shaping a unique karst landscape, so-called "marble glaciers". They include vast cave networks with valuable sedimentary records, archeological and paleontological remains.This paper presents the peculiar geodiversity and heritage values of Madre de Dios karst and a first geosites map of the archipelago, discussing the method of survey and assessment for such atypical karst geodiversity and geoheritage. The aims of these heritage studies are (i) the protection of this natural treasure - the island is under national protection status since 2007 - and (ii) the recognition of Madre de Dios as a World Heritage site by UNESCO.Situé à 50° sud en Patagonie chilienne, exploré par l'association Centre Terre depuis 2000, l'archipel de Madre de Dios abrite l'un des karsts les plus austraux de la planète. Bordé par l'Océan Pacifique à l'ouest, Madre de Dios est soumis à des conditions subpolaires océaniques avec des précipitations extrêmes (8 à 12 m/an) et de forts vents d'ouest permanents. L'archipel est formé de roches sédimentaires (dont calcaires) et plutoniques. La spéléogenèse a été influencée par les cycles glaciaires et les variations corrélatives du niveau marin. Ce contexte a permis le développement d'un karst binaire avec des taux record de dissolution et des modelés très spécifiques, donnant un paysage karstique unique au monde, surnommé "glaciers de marbre", dont les vastes réseaux spéléologiques contiennent des archives sédimentaires et des vestiges archéologiques et paléontologiques.Cet article présente la géodiversité et ls valeurs patrimoniales particulières du karst de Madre de Dios, ainsi qu'une première cartographie des géosites de l'archipel, dont les spécificités mettent à l'épreuve les méthodes d'inventaire et d'évaluation traditionnelles. L'objectif de telles études est double : (i) la préservation d ece qui est considéré depuis 2007 comme un Bien National Protégé par le gouvernement chilien, et (ii) l'inscription de Madre de Dios sur la liste du Patrimoine Mondial de l'UNESCO

The subpolar karst of Madre de Dios (Magallanes, Patagonia, Chile): a masterpiece of the world geoheritage

Situé à 50° sud en Patagonie chilienne, exploré par l'association Centre Terre depuis 2000, l'archipel de Madre de Dios abrite l'un des karsts les plus austraux de la planète. Bordé par l'Océan Pacifique à l'ouest, Madre de Dios est soumis à des conditions subpolaires océaniques avec des précipitations extrêmes (8 à 12 m/an) et de forts vents d'ouest permanents. L'archipel est formé de roches sédimentaires (dont calcaires) et plutoniques. La spéléogenèse a été influencée par les cycles glaciaires et les variations corrélatives du niveau marin. Ce contexte a permis le développement d'un karst binaire avec des taux record de dissolution et des modelés très spécifiques, donnant un paysage karstique unique au monde, surnommé "glaciers de marbre", dont les vastes réseaux spéléologiques contiennent des archives sédimentaires et des vestiges archéologiques et paléontologiques.Cet article présente la géodiversité et ls valeurs patrimoniales particulières du karst de Madre de Dios, ainsi qu'une première cartographie des géosites de l'archipel, dont les spécificités mettent à l'épreuve les méthodes d'inventaire et d'évaluation traditionnelles. L'objectif de telles études est double : (i) la préservation d ece qui est considéré depuis 2007 comme un Bien National Protégé par le gouvernement chilien, et (ii) l'inscription de Madre de Dios sur la liste du Patrimoine Mondial de l'UNESCO.Located at 50° South in Chilean Patagonia, explored by the association Centre Terre since 2000, Madre de Dios archipelago is one of the southernmost karst regions on Earth. Bordered by the Pacific Ocean to the west, Madre de Dios is exposed to subpolar oceanic conditions with extreme precipitation rates (8 to 12 m/year) and strong westerly winds. The archipelago is comprised of sedimentary (including limestone) and plutonic rocks. The speleogenesis interacted with successive glaciations and associated sea-level variations. This set of conditions induces the development of a binary karst characterized by record dissoultion rates and very specific landforms, shaping a unique karst landscape, so-called "marble glaciers". They include vast cave networks with valuable sedimentary records, archeological and paleontological remains.This paper presents the peculiar geodiversity and heritage values of Madre de Dios karst and a first geosites map of the archipelago, discussing the method of survey and assessment for such atypical karst geodiversity and geoheritage. The aims of these heritage studies are (i) the protection of this natural treasure - the island is under national protection status since 2007 - and (ii) the recognition of Madre de Dios as a World Heritage site by UNESCO

Le karst subpolaire de Madre de Dios (Magallanes, Patagonie chilienne) : un chef-d'oeuvre du géopatrimoine mondial

International audienceLocated at 50° South in Chilean Patagonia, explored by the association Centre Terre since 2000, Madre de Dios archipelago is one of the southernmost karst regions on Earth. Bordered by the Pacific Ocean to the west, Madre de Dios is exposed to subpolar oceanic conditions with extreme precipitation rates (8 to 12 m/year) and strong westerly winds. The archipelago is comprised of sedimentary (including limestone) and plutonic rocks. The speleogenesis interacted with successive glaciations and associated sea-level variations. This set of conditions induces the development of a binary karst characterized by record dissoultion rates and very specific landforms, shaping a unique karst landscape, so-called "marble glaciers". They include vast cave networks with valuable sedimentary records, archeological and paleontological remains.This paper presents the peculiar geodiversity and heritage values of Madre de Dios karst and a first geosites map of the archipelago, discussing the method of survey and assessment for such atypical karst geodiversity and geoheritage. The aims of these heritage studies are (i) the protection of this natural treasure - the island is under national protection status since 2007 - and (ii) the recognition of Madre de Dios as a World Heritage site by UNESCO.Situé à 50° sud en Patagonie chilienne, exploré par l'association Centre Terre depuis 2000, l'archipel de Madre de Dios abrite l'un des karsts les plus austraux de la planète. Bordé par l'Océan Pacifique à l'ouest, Madre de Dios est soumis à des conditions subpolaires océaniques avec des précipitations extrêmes (8 à 12 m/an) et de forts vents d'ouest permanents. L'archipel est formé de roches sédimentaires (dont calcaires) et plutoniques. La spéléogenèse a été influencée par les cycles glaciaires et les variations corrélatives du niveau marin. Ce contexte a permis le développement d'un karst binaire avec des taux record de dissolution et des modelés très spécifiques, donnant un paysage karstique unique au monde, surnommé "glaciers de marbre", dont les vastes réseaux spéléologiques contiennent des archives sédimentaires et des vestiges archéologiques et paléontologiques.Cet article présente la géodiversité et ls valeurs patrimoniales particulières du karst de Madre de Dios, ainsi qu'une première cartographie des géosites de l'archipel, dont les spécificités mettent à l'épreuve les méthodes d'inventaire et d'évaluation traditionnelles. L'objectif de telles études est double : (i) la préservation d ece qui est considéré depuis 2007 comme un Bien National Protégé par le gouvernement chilien, et (ii) l'inscription de Madre de Dios sur la liste du Patrimoine Mondial de l'UNESCO

Biocorrosion et art pariétal : une exclusion mutuelle à l’origine de vides archéologiques: Méthodologie, premiers résultats et nouvelles perspectives de recherche

International audienceFor millennia, men and animals have frequented the caves. They are therefore known for their archaeological remains, including rock art, but also for sheltering sometimes exceptionally large colonies of bats.The impact of bats on the underground environment has been identified for a few years with for example the development of bell holes on the ceiling and for the localized weathering caused by guano leachates on the walls. It now appears that this impact had been greatly underrated. Indeed, in recent years, research in karst science has integrated and developed this aspect, revealing the extended impact of biocorrosion, even in temperate latitudes. Thus, it is now accepted that the walls of caves that have been occupied at different times by large colonies of bats have been greatly modified. They are not only weathered, but also sometimes very largely reshaped, to the point that the volume of the gallery has considerably increased. New wall features, hitherto unknown, have been identified and a whole new catalog invites the re-reading of parietal morphologies.Obviously, in the initially decorated caves, rock art was the first affected by this retreat since it is located at the interface between the rock and the cave atmosphere. We can easily imagine that where biocorrosion was active, these traces of prehistoric artists may have disap-peared. The identification of the impact of biocorrosion therefore makes it possible to explain certain “voids”, without rock art, and above all to put into perspective the absence of rock art in some parts of the caves or even in some caves. In return, given the generalization of this phenomenon, we can then even ask why there are still decorated cavities? The most outstanding examples show that these are nearly always caves or parts of caves that were no longer accessible to bats. In these specific cases, a localized or generalized plugging of the caves blocked access to the bats after the passage of the artists, allowing the conservation of these fragile remains until today.It is therefore important now to review all the decorated caves, but also the cavities occupied or accessible during the Palaeolithic, to assess in detail the impact of biocorrosion. This necessarily interdisciplinary approach brings together geomorphologists, archaeolo-gists, geochemists, as well as climatologists, ethologists and microbiologists. Several interdisciplinary research programs, including a Collective Research Program (PCR), have therefore just been launched. The results of course concern archaeology, but also other aspects such as paleoenvironments, anthropization, ethology and the evolution of bats, and can be helpful for the conservation of archaeological sites and historical monuments.During 2021, more than a hundred cavities were visited in South of France. The identification of many features of biocorrosion has enabled us to begin the construction of a catalog allowing users of the underground environment (speleologists, karstologists, archae-ologists, chiropterologists, etc.) to identify these forms and to know how to interpret them. Several high-resolution 3D scans of cavities were performed to quantify these features. They will serve as a basis for aerological modelling and in particular to better understand the dissemination of acid gases released from guanos decay. More than 200 samples were taken for geochemical analyses, dating, extraction of paleoenvironmental data or to try to find DNA from ancient bat colonies. Many of them are still in progress, but the first results overpass our expectations. Thus, we were able to identify many types of phosphates and the complex reactions that lead to their formation in caves. They do not origin from megafauna bones as it was claimed before, but rather from the mineralization and leaching of bat guanos. Regarding guano deposits, we have developed a pollen extraction protocol and the first analyzes show the full potential for paleoenvironmental reconstructions. Thus, in one cores, we observed the fairly fast passage from the mixed oak forest to an open environment marked by agro-pastoral activities. We therefore perceive the impact of Man on the landscape during the end of the Neo-lithic. In the same core, isotopic analyzes show the appearance of a copper peak. It is contemporary with the phase of anthropization shown by the pollens and reflects the beginning of copper metallurgy which signal has been concentrated in the guano of bats, via insects.. This single example therefore shows the potential of guano studies, which now constitute a new proxy in karst environments that usually provide limited paleoenvironmental information.An important series of dating was also conducted in order to constrain the paces of this evolution and to be able to correlate it with human activities. Several U/Th dating have been conducted on speleothems weathered by biocorrosion and then sealed by a new generation of calcite. This shows us that biocorrosion can be old and sometimes go back to the Eemian. By its action of smoothing the walls of the caves, it prepared the background for the Paleolithic artists as in the caves of Pech Merle (Lot) or Chauvet (Ardèche). 14C dating of guanos also held their share of surprises, since it yielded sequences covering both the contemporary period and the historical periods, but also the entire Holocene and even the Upper Pleistocene. Some of these guanos have been dated to 48 ka BP. We will therefore soon have the possibility of studying the paleoenvironments of ancient periods, covering the entire history of our species, Homo sapiens, since its arrival in Europe. Thanks to the support of the MSH-T within the framework of the APEX 2021 call for projects, we have been able to develop cross-ap-proaches, involving Toulouse laboratories, allowing both to better characterize the processes of biocorrosion and correlative features that can be detected on the walls, but also to develop paleoenvironmental approaches. This research, also conducted within the frame-work of a Collective Research Program (Ministry of Culture), with the support of Occitanie region and PyGar research program, has enabled significant progress in this innovative but very promising field.Depuis des millénaires, les hommes et les animaux ont fréquenté le milieu souterrain. Les grottes sont donc réputées pour les vestiges archéologiques qu’elles contiennent, dont notamment des œuvres pariétales, mais aussi pour abriter des colonies de chauves-souris parfois très importantes.Si l’impact des chiroptères sur le milieu souterrain est connu depuis quelques années pour la formation de coupoles en bell holes au plafond et pour les altérations localisées provoquées par « les jus de guano » sur les parois et au sol, il apparaît désormais que cet impact avait été largement sous-évalué. En effet, ces dernières années, les recherches en karstologie ont intégré et développé cet aspect, révélant à quel point, même sous nos latitudes, l’impact de la biocorrosion est majeur. Ainsi, il est désormais acquis que les parois des grottes qui ont été occupées à différentes périodes par d’importantes colonies de chauves-souris ont été fortement modifiées. Elles sont non seulement altérées, mais aussi parfois très largement refaçonnées, au point que les sections de la galerie ont considérablement aug-menté. De nouvelles formes de parois, jusque-là interprétées différemment voire inconnues, ont été identifiées, procurant de nouvelles clés de lecture des morphologies pariétales.Dans les grottes initialement ornées, les œuvres pariétales ont été les premières touchées par ce recul puisqu’elles se situent à l’interface entre la roche et l’atmosphère de la cavité. On peut donc imaginer que là où la biocorrosion a agi, les traces des artistes de la Préhistoire ont disparu. L’identification de l’impact de la biocorrosion permet donc d’expliquer certains « vides » archéologiques, et surtout de rela-tiviser les absences d’œuvres dans certaines parties de cavité, voire dans certaines grottes. En retour, compte tenu de la généralisation de ce phénomène, on peut alors s’étonner qu’il reste encore des cavités ornées. Les exemples les plus célèbres (Mas d’Azil, Ariège ; Chauvet, Ardèche ; Cosquer, Bouche-du-Rhône ; Lascaux, Dordogne…) montrent qu’il s’agit la plupart du temps de grottes ou de parties de grottes qui n’étaient plus accessibles aux chiroptères ; c’est-à-dire qu’après le passage des artistes, une fermeture localisée ou généralisée de la cavité a bloqué l’accès aux chauves-souris, permettant la préservation de ces œuvres fragiles jusqu’à leur découverte. Il est donc important désormais de revoir l’ensemble des grottes ornées, mais aussi des cavités occupées au cours du Paléolithique pour évaluer en détail l’impact de la biocorrosion. Cette approche, nécessairement interdisciplinaire, regroupe des géomorphologues, des archéologues, des géochimistes, et également des climatologues, des éthologues et des microbiologistes. Plusieurs programmes de recherche interdisciplinaires, dont un programme collectif de recherche (PCR), viennent donc d’être lancés. Les résultats concernent bien entendu l’archéologie et aussi d’autres aspects comme les paléoenvironnements, l’anthropisation, l’éthologie et l’évolution des espèces de chiroptères, mais également la protection des sites archéologiques, du patrimoine bâti et des chauves-souris, elles aussi en danger

Biocorrosion et art pariétal : une exclusion mutuelle à l’origine de vides archéologiques: Méthodologie, premiers résultats et nouvelles perspectives de recherche

International audienceFor millennia, men and animals have frequented the caves. They are therefore known for their archaeological remains, including rock art, but also for sheltering sometimes exceptionally large colonies of bats.The impact of bats on the underground environment has been identified for a few years with for example the development of bell holes on the ceiling and for the localized weathering caused by guano leachates on the walls. It now appears that this impact had been greatly underrated. Indeed, in recent years, research in karst science has integrated and developed this aspect, revealing the extended impact of biocorrosion, even in temperate latitudes. Thus, it is now accepted that the walls of caves that have been occupied at different times by large colonies of bats have been greatly modified. They are not only weathered, but also sometimes very largely reshaped, to the point that the volume of the gallery has considerably increased. New wall features, hitherto unknown, have been identified and a whole new catalog invites the re-reading of parietal morphologies.Obviously, in the initially decorated caves, rock art was the first affected by this retreat since it is located at the interface between the rock and the cave atmosphere. We can easily imagine that where biocorrosion was active, these traces of prehistoric artists may have disap-peared. The identification of the impact of biocorrosion therefore makes it possible to explain certain “voids”, without rock art, and above all to put into perspective the absence of rock art in some parts of the caves or even in some caves. In return, given the generalization of this phenomenon, we can then even ask why there are still decorated cavities? The most outstanding examples show that these are nearly always caves or parts of caves that were no longer accessible to bats. In these specific cases, a localized or generalized plugging of the caves blocked access to the bats after the passage of the artists, allowing the conservation of these fragile remains until today.It is therefore important now to review all the decorated caves, but also the cavities occupied or accessible during the Palaeolithic, to assess in detail the impact of biocorrosion. This necessarily interdisciplinary approach brings together geomorphologists, archaeolo-gists, geochemists, as well as climatologists, ethologists and microbiologists. Several interdisciplinary research programs, including a Collective Research Program (PCR), have therefore just been launched. The results of course concern archaeology, but also other aspects such as paleoenvironments, anthropization, ethology and the evolution of bats, and can be helpful for the conservation of archaeological sites and historical monuments.During 2021, more than a hundred cavities were visited in South of France. The identification of many features of biocorrosion has enabled us to begin the construction of a catalog allowing users of the underground environment (speleologists, karstologists, archae-ologists, chiropterologists, etc.) to identify these forms and to know how to interpret them. Several high-resolution 3D scans of cavities were performed to quantify these features. They will serve as a basis for aerological modelling and in particular to better understand the dissemination of acid gases released from guanos decay. More than 200 samples were taken for geochemical analyses, dating, extraction of paleoenvironmental data or to try to find DNA from ancient bat colonies. Many of them are still in progress, but the first results overpass our expectations. Thus, we were able to identify many types of phosphates and the complex reactions that lead to their formation in caves. They do not origin from megafauna bones as it was claimed before, but rather from the mineralization and leaching of bat guanos. Regarding guano deposits, we have developed a pollen extraction protocol and the first analyzes show the full potential for paleoenvironmental reconstructions. Thus, in one cores, we observed the fairly fast passage from the mixed oak forest to an open environment marked by agro-pastoral activities. We therefore perceive the impact of Man on the landscape during the end of the Neo-lithic. In the same core, isotopic analyzes show the appearance of a copper peak. It is contemporary with the phase of anthropization shown by the pollens and reflects the beginning of copper metallurgy which signal has been concentrated in the guano of bats, via insects.. This single example therefore shows the potential of guano studies, which now constitute a new proxy in karst environments that usually provide limited paleoenvironmental information.An important series of dating was also conducted in order to constrain the paces of this evolution and to be able to correlate it with human activities. Several U/Th dating have been conducted on speleothems weathered by biocorrosion and then sealed by a new generation of calcite. This shows us that biocorrosion can be old and sometimes go back to the Eemian. By its action of smoothing the walls of the caves, it prepared the background for the Paleolithic artists as in the caves of Pech Merle (Lot) or Chauvet (Ardèche). 14C dating of guanos also held their share of surprises, since it yielded sequences covering both the contemporary period and the historical periods, but also the entire Holocene and even the Upper Pleistocene. Some of these guanos have been dated to 48 ka BP. We will therefore soon have the possibility of studying the paleoenvironments of ancient periods, covering the entire history of our species, Homo sapiens, since its arrival in Europe. Thanks to the support of the MSH-T within the framework of the APEX 2021 call for projects, we have been able to develop cross-ap-proaches, involving Toulouse laboratories, allowing both to better characterize the processes of biocorrosion and correlative features that can be detected on the walls, but also to develop paleoenvironmental approaches. This research, also conducted within the frame-work of a Collective Research Program (Ministry of Culture), with the support of Occitanie region and PyGar research program, has enabled significant progress in this innovative but very promising field.Depuis des millénaires, les hommes et les animaux ont fréquenté le milieu souterrain. Les grottes sont donc réputées pour les vestiges archéologiques qu’elles contiennent, dont notamment des œuvres pariétales, mais aussi pour abriter des colonies de chauves-souris parfois très importantes.Si l’impact des chiroptères sur le milieu souterrain est connu depuis quelques années pour la formation de coupoles en bell holes au plafond et pour les altérations localisées provoquées par « les jus de guano » sur les parois et au sol, il apparaît désormais que cet impact avait été largement sous-évalué. En effet, ces dernières années, les recherches en karstologie ont intégré et développé cet aspect, révélant à quel point, même sous nos latitudes, l’impact de la biocorrosion est majeur. Ainsi, il est désormais acquis que les parois des grottes qui ont été occupées à différentes périodes par d’importantes colonies de chauves-souris ont été fortement modifiées. Elles sont non seulement altérées, mais aussi parfois très largement refaçonnées, au point que les sections de la galerie ont considérablement aug-menté. De nouvelles formes de parois, jusque-là interprétées différemment voire inconnues, ont été identifiées, procurant de nouvelles clés de lecture des morphologies pariétales.Dans les grottes initialement ornées, les œuvres pariétales ont été les premières touchées par ce recul puisqu’elles se situent à l’interface entre la roche et l’atmosphère de la cavité. On peut donc imaginer que là où la biocorrosion a agi, les traces des artistes de la Préhistoire ont disparu. L’identification de l’impact de la biocorrosion permet donc d’expliquer certains « vides » archéologiques, et surtout de rela-tiviser les absences d’œuvres dans certaines parties de cavité, voire dans certaines grottes. En retour, compte tenu de la généralisation de ce phénomène, on peut alors s’étonner qu’il reste encore des cavités ornées. Les exemples les plus célèbres (Mas d’Azil, Ariège ; Chauvet, Ardèche ; Cosquer, Bouche-du-Rhône ; Lascaux, Dordogne…) montrent qu’il s’agit la plupart du temps de grottes ou de parties de grottes qui n’étaient plus accessibles aux chiroptères ; c’est-à-dire qu’après le passage des artistes, une fermeture localisée ou généralisée de la cavité a bloqué l’accès aux chauves-souris, permettant la préservation de ces œuvres fragiles jusqu’à leur découverte. Il est donc important désormais de revoir l’ensemble des grottes ornées, mais aussi des cavités occupées au cours du Paléolithique pour évaluer en détail l’impact de la biocorrosion. Cette approche, nécessairement interdisciplinaire, regroupe des géomorphologues, des archéologues, des géochimistes, et également des climatologues, des éthologues et des microbiologistes. Plusieurs programmes de recherche interdisciplinaires, dont un programme collectif de recherche (PCR), viennent donc d’être lancés. Les résultats concernent bien entendu l’archéologie et aussi d’autres aspects comme les paléoenvironnements, l’anthropisation, l’éthologie et l’évolution des espèces de chiroptères, mais également la protection des sites archéologiques, du patrimoine bâti et des chauves-souris, elles aussi en danger

Biocorrosion et art pariétal : une exclusion mutuelle à l’origine de vides archéologiques: Méthodologie, premiers résultats et nouvelles perspectives de recherche

International audienceFor millennia, men and animals have frequented the caves. They are therefore known for their archaeological remains, including rock art, but also for sheltering sometimes exceptionally large colonies of bats.The impact of bats on the underground environment has been identified for a few years with for example the development of bell holes on the ceiling and for the localized weathering caused by guano leachates on the walls. It now appears that this impact had been greatly underrated. Indeed, in recent years, research in karst science has integrated and developed this aspect, revealing the extended impact of biocorrosion, even in temperate latitudes. Thus, it is now accepted that the walls of caves that have been occupied at different times by large colonies of bats have been greatly modified. They are not only weathered, but also sometimes very largely reshaped, to the point that the volume of the gallery has considerably increased. New wall features, hitherto unknown, have been identified and a whole new catalog invites the re-reading of parietal morphologies.Obviously, in the initially decorated caves, rock art was the first affected by this retreat since it is located at the interface between the rock and the cave atmosphere. We can easily imagine that where biocorrosion was active, these traces of prehistoric artists may have disap-peared. The identification of the impact of biocorrosion therefore makes it possible to explain certain “voids”, without rock art, and above all to put into perspective the absence of rock art in some parts of the caves or even in some caves. In return, given the generalization of this phenomenon, we can then even ask why there are still decorated cavities? The most outstanding examples show that these are nearly always caves or parts of caves that were no longer accessible to bats. In these specific cases, a localized or generalized plugging of the caves blocked access to the bats after the passage of the artists, allowing the conservation of these fragile remains until today.It is therefore important now to review all the decorated caves, but also the cavities occupied or accessible during the Palaeolithic, to assess in detail the impact of biocorrosion. This necessarily interdisciplinary approach brings together geomorphologists, archaeolo-gists, geochemists, as well as climatologists, ethologists and microbiologists. Several interdisciplinary research programs, including a Collective Research Program (PCR), have therefore just been launched. The results of course concern archaeology, but also other aspects such as paleoenvironments, anthropization, ethology and the evolution of bats, and can be helpful for the conservation of archaeological sites and historical monuments.During 2021, more than a hundred cavities were visited in South of France. The identification of many features of biocorrosion has enabled us to begin the construction of a catalog allowing users of the underground environment (speleologists, karstologists, archae-ologists, chiropterologists, etc.) to identify these forms and to know how to interpret them. Several high-resolution 3D scans of cavities were performed to quantify these features. They will serve as a basis for aerological modelling and in particular to better understand the dissemination of acid gases released from guanos decay. More than 200 samples were taken for geochemical analyses, dating, extraction of paleoenvironmental data or to try to find DNA from ancient bat colonies. Many of them are still in progress, but the first results overpass our expectations. Thus, we were able to identify many types of phosphates and the complex reactions that lead to their formation in caves. They do not origin from megafauna bones as it was claimed before, but rather from the mineralization and leaching of bat guanos. Regarding guano deposits, we have developed a pollen extraction protocol and the first analyzes show the full potential for paleoenvironmental reconstructions. Thus, in one cores, we observed the fairly fast passage from the mixed oak forest to an open environment marked by agro-pastoral activities. We therefore perceive the impact of Man on the landscape during the end of the Neo-lithic. In the same core, isotopic analyzes show the appearance of a copper peak. It is contemporary with the phase of anthropization shown by the pollens and reflects the beginning of copper metallurgy which signal has been concentrated in the guano of bats, via insects.. This single example therefore shows the potential of guano studies, which now constitute a new proxy in karst environments that usually provide limited paleoenvironmental information.An important series of dating was also conducted in order to constrain the paces of this evolution and to be able to correlate it with human activities. Several U/Th dating have been conducted on speleothems weathered by biocorrosion and then sealed by a new generation of calcite. This shows us that biocorrosion can be old and sometimes go back to the Eemian. By its action of smoothing the walls of the caves, it prepared the background for the Paleolithic artists as in the caves of Pech Merle (Lot) or Chauvet (Ardèche). 14C dating of guanos also held their share of surprises, since it yielded sequences covering both the contemporary period and the historical periods, but also the entire Holocene and even the Upper Pleistocene. Some of these guanos have been dated to 48 ka BP. We will therefore soon have the possibility of studying the paleoenvironments of ancient periods, covering the entire history of our species, Homo sapiens, since its arrival in Europe. Thanks to the support of the MSH-T within the framework of the APEX 2021 call for projects, we have been able to develop cross-ap-proaches, involving Toulouse laboratories, allowing both to better characterize the processes of biocorrosion and correlative features that can be detected on the walls, but also to develop paleoenvironmental approaches. This research, also conducted within the frame-work of a Collective Research Program (Ministry of Culture), with the support of Occitanie region and PyGar research program, has enabled significant progress in this innovative but very promising field.Depuis des millénaires, les hommes et les animaux ont fréquenté le milieu souterrain. Les grottes sont donc réputées pour les vestiges archéologiques qu’elles contiennent, dont notamment des œuvres pariétales, mais aussi pour abriter des colonies de chauves-souris parfois très importantes.Si l’impact des chiroptères sur le milieu souterrain est connu depuis quelques années pour la formation de coupoles en bell holes au plafond et pour les altérations localisées provoquées par « les jus de guano » sur les parois et au sol, il apparaît désormais que cet impact avait été largement sous-évalué. En effet, ces dernières années, les recherches en karstologie ont intégré et développé cet aspect, révélant à quel point, même sous nos latitudes, l’impact de la biocorrosion est majeur. Ainsi, il est désormais acquis que les parois des grottes qui ont été occupées à différentes périodes par d’importantes colonies de chauves-souris ont été fortement modifiées. Elles sont non seulement altérées, mais aussi parfois très largement refaçonnées, au point que les sections de la galerie ont considérablement aug-menté. De nouvelles formes de parois, jusque-là interprétées différemment voire inconnues, ont été identifiées, procurant de nouvelles clés de lecture des morphologies pariétales.Dans les grottes initialement ornées, les œuvres pariétales ont été les premières touchées par ce recul puisqu’elles se situent à l’interface entre la roche et l’atmosphère de la cavité. On peut donc imaginer que là où la biocorrosion a agi, les traces des artistes de la Préhistoire ont disparu. L’identification de l’impact de la biocorrosion permet donc d’expliquer certains « vides » archéologiques, et surtout de rela-tiviser les absences d’œuvres dans certaines parties de cavité, voire dans certaines grottes. En retour, compte tenu de la généralisation de ce phénomène, on peut alors s’étonner qu’il reste encore des cavités ornées. Les exemples les plus célèbres (Mas d’Azil, Ariège ; Chauvet, Ardèche ; Cosquer, Bouche-du-Rhône ; Lascaux, Dordogne…) montrent qu’il s’agit la plupart du temps de grottes ou de parties de grottes qui n’étaient plus accessibles aux chiroptères ; c’est-à-dire qu’après le passage des artistes, une fermeture localisée ou généralisée de la cavité a bloqué l’accès aux chauves-souris, permettant la préservation de ces œuvres fragiles jusqu’à leur découverte. Il est donc important désormais de revoir l’ensemble des grottes ornées, mais aussi des cavités occupées au cours du Paléolithique pour évaluer en détail l’impact de la biocorrosion. Cette approche, nécessairement interdisciplinaire, regroupe des géomorphologues, des archéologues, des géochimistes, et également des climatologues, des éthologues et des microbiologistes. Plusieurs programmes de recherche interdisciplinaires, dont un programme collectif de recherche (PCR), viennent donc d’être lancés. Les résultats concernent bien entendu l’archéologie et aussi d’autres aspects comme les paléoenvironnements, l’anthropisation, l’éthologie et l’évolution des espèces de chiroptères, mais également la protection des sites archéologiques, du patrimoine bâti et des chauves-souris, elles aussi en danger

Biocorrosion et art pariétal : une exclusion mutuelle à l’origine de vides archéologiques: Méthodologie, premiers résultats et nouvelles perspectives de recherche

International audienceFor millennia, men and animals have frequented the caves. They are therefore known for their archaeological remains, including rock art, but also for sheltering sometimes exceptionally large colonies of bats.The impact of bats on the underground environment has been identified for a few years with for example the development of bell holes on the ceiling and for the localized weathering caused by guano leachates on the walls. It now appears that this impact had been greatly underrated. Indeed, in recent years, research in karst science has integrated and developed this aspect, revealing the extended impact of biocorrosion, even in temperate latitudes. Thus, it is now accepted that the walls of caves that have been occupied at different times by large colonies of bats have been greatly modified. They are not only weathered, but also sometimes very largely reshaped, to the point that the volume of the gallery has considerably increased. New wall features, hitherto unknown, have been identified and a whole new catalog invites the re-reading of parietal morphologies.Obviously, in the initially decorated caves, rock art was the first affected by this retreat since it is located at the interface between the rock and the cave atmosphere. We can easily imagine that where biocorrosion was active, these traces of prehistoric artists may have disap-peared. The identification of the impact of biocorrosion therefore makes it possible to explain certain “voids”, without rock art, and above all to put into perspective the absence of rock art in some parts of the caves or even in some caves. In return, given the generalization of this phenomenon, we can then even ask why there are still decorated cavities? The most outstanding examples show that these are nearly always caves or parts of caves that were no longer accessible to bats. In these specific cases, a localized or generalized plugging of the caves blocked access to the bats after the passage of the artists, allowing the conservation of these fragile remains until today.It is therefore important now to review all the decorated caves, but also the cavities occupied or accessible during the Palaeolithic, to assess in detail the impact of biocorrosion. This necessarily interdisciplinary approach brings together geomorphologists, archaeolo-gists, geochemists, as well as climatologists, ethologists and microbiologists. Several interdisciplinary research programs, including a Collective Research Program (PCR), have therefore just been launched. The results of course concern archaeology, but also other aspects such as paleoenvironments, anthropization, ethology and the evolution of bats, and can be helpful for the conservation of archaeological sites and historical monuments.During 2021, more than a hundred cavities were visited in South of France. The identification of many features of biocorrosion has enabled us to begin the construction of a catalog allowing users of the underground environment (speleologists, karstologists, archae-ologists, chiropterologists, etc.) to identify these forms and to know how to interpret them. Several high-resolution 3D scans of cavities were performed to quantify these features. They will serve as a basis for aerological modelling and in particular to better understand the dissemination of acid gases released from guanos decay. More than 200 samples were taken for geochemical analyses, dating, extraction of paleoenvironmental data or to try to find DNA from ancient bat colonies. Many of them are still in progress, but the first results overpass our expectations. Thus, we were able to identify many types of phosphates and the complex reactions that lead to their formation in caves. They do not origin from megafauna bones as it was claimed before, but rather from the mineralization and leaching of bat guanos. Regarding guano deposits, we have developed a pollen extraction protocol and the first analyzes show the full potential for paleoenvironmental reconstructions. Thus, in one cores, we observed the fairly fast passage from the mixed oak forest to an open environment marked by agro-pastoral activities. We therefore perceive the impact of Man on the landscape during the end of the Neo-lithic. In the same core, isotopic analyzes show the appearance of a copper peak. It is contemporary with the phase of anthropization shown by the pollens and reflects the beginning of copper metallurgy which signal has been concentrated in the guano of bats, via insects.. This single example therefore shows the potential of guano studies, which now constitute a new proxy in karst environments that usually provide limited paleoenvironmental information.An important series of dating was also conducted in order to constrain the paces of this evolution and to be able to correlate it with human activities. Several U/Th dating have been conducted on speleothems weathered by biocorrosion and then sealed by a new generation of calcite. This shows us that biocorrosion can be old and sometimes go back to the Eemian. By its action of smoothing the walls of the caves, it prepared the background for the Paleolithic artists as in the caves of Pech Merle (Lot) or Chauvet (Ardèche). 14C dating of guanos also held their share of surprises, since it yielded sequences covering both the contemporary period and the historical periods, but also the entire Holocene and even the Upper Pleistocene. Some of these guanos have been dated to 48 ka BP. We will therefore soon have the possibility of studying the paleoenvironments of ancient periods, covering the entire history of our species, Homo sapiens, since its arrival in Europe. Thanks to the support of the MSH-T within the framework of the APEX 2021 call for projects, we have been able to develop cross-ap-proaches, involving Toulouse laboratories, allowing both to better characterize the processes of biocorrosion and correlative features that can be detected on the walls, but also to develop paleoenvironmental approaches. This research, also conducted within the frame-work of a Collective Research Program (Ministry of Culture), with the support of Occitanie region and PyGar research program, has enabled significant progress in this innovative but very promising field.Depuis des millénaires, les hommes et les animaux ont fréquenté le milieu souterrain. Les grottes sont donc réputées pour les vestiges archéologiques qu’elles contiennent, dont notamment des œuvres pariétales, mais aussi pour abriter des colonies de chauves-souris parfois très importantes.Si l’impact des chiroptères sur le milieu souterrain est connu depuis quelques années pour la formation de coupoles en bell holes au plafond et pour les altérations localisées provoquées par « les jus de guano » sur les parois et au sol, il apparaît désormais que cet impact avait été largement sous-évalué. En effet, ces dernières années, les recherches en karstologie ont intégré et développé cet aspect, révélant à quel point, même sous nos latitudes, l’impact de la biocorrosion est majeur. Ainsi, il est désormais acquis que les parois des grottes qui ont été occupées à différentes périodes par d’importantes colonies de chauves-souris ont été fortement modifiées. Elles sont non seulement altérées, mais aussi parfois très largement refaçonnées, au point que les sections de la galerie ont considérablement aug-menté. De nouvelles formes de parois, jusque-là interprétées différemment voire inconnues, ont été identifiées, procurant de nouvelles clés de lecture des morphologies pariétales.Dans les grottes initialement ornées, les œuvres pariétales ont été les premières touchées par ce recul puisqu’elles se situent à l’interface entre la roche et l’atmosphère de la cavité. On peut donc imaginer que là où la biocorrosion a agi, les traces des artistes de la Préhistoire ont disparu. L’identification de l’impact de la biocorrosion permet donc d’expliquer certains « vides » archéologiques, et surtout de rela-tiviser les absences d’œuvres dans certaines parties de cavité, voire dans certaines grottes. En retour, compte tenu de la généralisation de ce phénomène, on peut alors s’étonner qu’il reste encore des cavités ornées. Les exemples les plus célèbres (Mas d’Azil, Ariège ; Chauvet, Ardèche ; Cosquer, Bouche-du-Rhône ; Lascaux, Dordogne…) montrent qu’il s’agit la plupart du temps de grottes ou de parties de grottes qui n’étaient plus accessibles aux chiroptères ; c’est-à-dire qu’après le passage des artistes, une fermeture localisée ou généralisée de la cavité a bloqué l’accès aux chauves-souris, permettant la préservation de ces œuvres fragiles jusqu’à leur découverte. Il est donc important désormais de revoir l’ensemble des grottes ornées, mais aussi des cavités occupées au cours du Paléolithique pour évaluer en détail l’impact de la biocorrosion. Cette approche, nécessairement interdisciplinaire, regroupe des géomorphologues, des archéologues, des géochimistes, et également des climatologues, des éthologues et des microbiologistes. Plusieurs programmes de recherche interdisciplinaires, dont un programme collectif de recherche (PCR), viennent donc d’être lancés. Les résultats concernent bien entendu l’archéologie et aussi d’autres aspects comme les paléoenvironnements, l’anthropisation, l’éthologie et l’évolution des espèces de chiroptères, mais également la protection des sites archéologiques, du patrimoine bâti et des chauves-souris, elles aussi en danger