A TOUCH OF FRANCE – Lascaux: preserving a 20 000-year old legacy of Paleolithic art






Muriel MAURIAC
General Heritage Curator
Curator of the Lascaux Cave

Lascaux: preserving a 20 000-year old legacy of Paleolithic art


by M. Mauriac, France



Redolent of a “Boys’ Own” or “Famous Five” adventure story, the discovery by four teenagers and their dog of a Paleolithic painted cave in southwestern France, on 12 September in 1940, changed humanity’s perception of our distant, prehistoric, ancestors. The close to 2000 painted figures easily rank among the most impressive and beautiful in the world. After the war, the 20 000-year-old Lascaux Cave was opened to the general public. Before long, though, the effects of the ever-swelling number of visitors destabilized the cave’s fragile natural environment, and the cave became what is tantamount to a “patient” in need of close “medical” attention from hosts of experts to diagnose and treat its many ailments and avoid a treasure being lost to humanity. Humidity changes, increased carbon dioxide levels, rises in temperature from artificial lighting, changes in climate and in the cave’s environmental conditions, contributed to trigger the likes of “diseases” (green sickness, white sickness, black stains…) caused by infestations by a variety of organisms, the list of which reads like a bacteriology and pathology lab report. Thus, molds and fungi (Fusarium solani, Ochroconis lascauxensis and O. anomala, Chrysosporium, Gliocladium, Gliomastix, Paecilomyces, Trichoderma, Verticillium), algae (Bracteacoccus minor), bacteria (Pseudomonas fluorescens) required treatment with antifungals and antibiotics (streptomycin, penicillin, polymyxin,) and various agents (formalin, benzalkonium chloride, quicklime), and huge apparatuses and systems to ensure adequate climatic conditions. Lascaux was unwillingly transformed into a place of experimentation, of heuristics, a laboratory for the conservation of parietal art. The cave was closed to the public in 1963, and listed as a world heritage site by UNESCO in 1979. An underground replica of the cave opened in 1983, known as Lascaux II, featuring an amazingly faithful full-sized facsimile of the topography (down to the very texture of the cave’s geological characteristics) and paintings of the Great Hall of the Bulls and the Axial Gallery, and is visited by approximately 250 000 tourists every year. This was followed in 2009 by the creation of Lascaux III, a major traveling exhibition of five facsimiles with paintings not reproduced in Lascaux II. A mammoth project, Lascaux IV, a complete replica of the cave and its paintings, is due to open in 2016 and is anticipated to attract 400 000 visitors every year.

Medicographia. 2013;36:238-252 (see French abstract on page 252)



Top-of-page frieze: based on drawings by Henri Breuil
of paintings in the Combarelles cave at Les-Eyzies-de-Tayac.

© RMN-Grand Palais (Musée de la Préhistoire des Eyzies)/Franck Raux.




Hall of the Bulls at Lascaux. © akg/Glasshouse Images.





On 8 September 1940, in the early years of World War II, but far removed from its turmoil, 17-year old Marcel Ravidat was taking a stroll with his dog on a pine- and oak-covered hill above Montignac, in southwestern France, in the picturesque Dordogne region. Suddenly, his russet-haired setter-terrier started scratching around in a hole at the base of a long-uprooted tree. Intrigued, Marcel rolled stones away to uncover the entrance of a seemingly quite deep cave. Returning four days later to explore further, Marcel happened across three other teenagers, Jacques Marsal, Simon Coëncas, and Georges Agniel who joined him in his quest. Using makeshift tools, the four boys widened the hole and stumbled into the cave. Before long, painted likenesses of wild bulls and horses running across the lamplit cave walls flickered into life, leaving the little group gaping in amazement and awe. Torn between keeping the discovery to themselves and revealing their find to the outside world, the youngsters confided in the local primary school teacher, Léon Laval. Immediately realizing the significance of their find, Laval sought the advice of Henri Breuil, the “Pope of prehistory,” who confirmed that the magnificent paintings were a major work of long gone prehistoric humans.



Hall of the Bulls in October 1940. In the center, hand outreached, Count Begouën (in front) and Father Henri Breuil. In the foreground,
sitting, two of the discoverers: Jacques Marsal (seen in profile) and Marcel Ravidat (facing). Work is under way to lower and smoothen out
the floor of the cave to make its access easier for visitors. Laval Collection / Fonds Laval.




Frieze of the Swimming Stags in the Nave. © Bridgeman Art Library.


Lascaux Cave has since been recognized as among the finest ever found. The wartime discovery marked a sea change in the way we view our prehistoric ancestors, and after the war the 20 000-year-old Lascaux Cave was opened to the general public. Before long though, the effects of the ever-swelling number of visitors destabilized the cave’s fragile natural environment. Mold, fungal, and bacterial infestation, humidity changes, increased carbon dioxide levels endangered the paintings, and Lascaux was unwillingly transformed into a place of experimentation, of heuristics, a laboratory for the conservation of parietal art. Thus it is that from conundrum to solution and back again the conservation of Lascaux has for the last seventy years been shedding light on the complex environments of painted caves.

As to the four teenagers who discovered the cave, their lives forever changed, different fates awaited them in occupied war-time France. Simon Coëncas returned to Nazi-occupied Paris, where in 1942 he and his family were arrested and held at the Drancy internment camp. Because of their youth, the Red Cross was able to pluck from danger Simon and his sister Éliette, but the rest of the family was deported to Auschwitz and exterminated. On vacation at his grandmother’s house at the time of the discovery, George Agniel returned home to Nogent-sur-Marne, near Paris. Jacques Marsal and Marcel Ravidat, both locals, looked after the cave and took part in the early development of the site, before Jacques was requisitioned for forced labor in Germany and Marcel joined the French Resistance. At the Liberation of France, they became guides and wardens at Lascaux.



Layout of the Lascaux Cave. © MCC-CNP.




Lascaux cave

France’s Dordogne region is rich in prehistoric sites, but the discovery of Lascaux stirred the imagination as none other. Lay public and experts alike marveled at the quality of the paintings, the freshness of the colors, the richness of the representations— nearly 2000 painted and engraved abstract signs and figures, including over 900 animals, and but one human figure. Recognizing its heritage value just months after the discovery, the French government classed Lascaux as a historic monument, and in 1979 UNESCO listed it as a world heritage site, along with 14 other prehistoric sites in the Vézère Valley.

Set apart from other cave art sites around Eyzies-de-Tayac, Lascaux is unusual for its location at shallow depth, modest size (volume approximately 3000 m³), and high carbon dioxide content. In its geological setting of limestone, the 235-meter- long cave complex begins with the Hall of the Bulls and continues into the Axial Gallery. The Passageway leads on the right to the Apse, which goes down to the lower network of the Shaft, and straight on to the Nave followed by the Mondmilch Gallery and lastly the Chamber of Felines. Horses account for 60% of the animals depicted, and stags 14%. Reindeer are pictured but once, yet played a major role in the lives of these prehistoric people, who lived at a time dubbed the Age of the Reindeer, providing most of their meat, fat for lamps, hides for clothing and hut coverings, and bones for needles. Aurochs (long-horned wild oxen, now extinct, the ancestors of domestic cattle) account for less than 5% of the animal images, though one painting of a bull is among the largest (5 meters long) in prehistoric cave art. Pictured also are bison, ibexes, felines, one bird, one bear, and the now extinct wooly rhinoceros. From one sector to the next, the cave varies substantially in mineralogical characteristics. In the Hall of the Bulls and the Axial Gallery, the limestone and calcite wall surfaces are too hard or irregular for engraving work, and instead color pigments were applied by dabbing or spraying. In contrast, the Passageway, Apse, and Nave have soft limestone walls with little or no calcite and the images covering them are engraved, painted, and drawn. The very nature of the walls partly explains the survival of these artworks, though some were already damaged when discovered in 1940. Paleolithic humans took subtle advantage of the physical characteristics of the walls to heighten effects, and employed a multiplicity of techniques, as attested by the wealth of archaeological materials discovered by the prehistorian André Glory and the palette of pigments: iron oxide for reds, browns, and ochers, and manganese oxide for blacks (pyrolusite, manganite, romanechite), particularly in the Hall of the Bulls and the Axial Gallery.



Axial Gallery, with Second and Third Chinese Horses. © MCC-CNP.



Upside-Down Horse in the Meander prolonging the Axial Gallery.
© MCC-CNP.




Apse, engraved Horse. © MCC-CNP.


In the weeks following the discovery of the cave, the owner of the land, Count Charles-Emmanuel de la Rochefoucauld, had improvements made to facilitate access, by developing the hole through which Marcel Ravidat and his friends had entered the cave. But from 1947, the Count financed substantial work done without any real archaeological supervision: creation of the monumental entrance and of the stairway for access, lowering of floors, as in the Passageway where the headroom was insufficient for comfortable movement. This work altered the seasonal inflow of rainfall as well as the overall volume of the cave, as several tons of earth were removed or tipped down the haft. These alterations allowed Lascaux to be opened to the public, in July 1948, but the immense interest generated came at a cost. By making this prehistoric masterpiece available to ever increasing numbers of visitors— 1800 a day in 1960—the cave’s ecosystem was perturbed and conservation problems began.

The troubled preservation of Lascaux: 1948-1963

It would be a mistake to imagine that the Lascaux Cave environment had been stable for 20 000 years. Some paintings had suffered irreversible damage well before their discovery. Others have largely disappeared from the walls in the Passageway, and engraved lines and vestiges of pigments are all that remain. This deterioration may perhaps be explained by air currents linked to the presence of calcite rims recently dated by the French Atomic Energy Commission to around 8000 years before the present day.

A year after Lascaux was opened to the public, mold appeared on the walls and two airlocks were installed to create a buffer zone between the cave and the outside world. By 1955, intermittent condensation on the walls, excessive temperatures, and high carbon dioxide levels were becoming a grave concern and prompted new attempts to restore the climatic balance upset by the influx of visitors, some 30 000 that year. Chief architect Yves-Marie Froidevaux designed a climatic regulation system to inject air at 14°C and suck out used air, thus renewing the atmosphere in the visitor areas and reducing carbon dioxide levels. But the removal of 440 cubic meters of earth and rock (about 1200 tons), for the installation of ventilation ducts, altered the volumetric configuration of several parts of the cave and irremediably destroyed some archaeological layers, despite André Glory’s supervision, now deemed insufficient. Tasked also with studying the paintings, Glory took copious notes on the cave layout, drew sketches, and, despite the meager human and material resources at his disposal, collected extensive information and many objects: flint tools and lithic cores, two needles, one of which was for sewing, charcoal fragments, reindeer bones, pigments, and the famous lamp now on display at the National Museum of Prehistory in Eyzies-de-Tayac.



Overall view of the Hall of the Bulls. © MCC-CNP


This conservation work proved insufficient and in 1960 the curator at Lascaux, Max Sarradet, noted the presence of green stains on the walls of the Hall of the Bulls and of the Axial Gallery. Faced with this alarming situation, André Malraux, the Minister of Cultural Affairs, created a scientific commission “to study the changes inside the cave, find remedies, and bring the cave back to stable conditions.” In April 1963, the commission obliged Count de la Rochefoucauld to close Lascaux. Analyses revealed a diversity of associated microbes, the main genus being Bracteacoccus of the order of green algae Chlorococcales. To curb this contamination, the commission recommended spraying antibiotics and formaldehyde solutions on the floors and walls. The worrisome formation of a thin layer of white calcite on the walls prompted the commission to set up daily climatic measurements and to remove Froidevaux’s machine, which was deemed unsuitable. In 1965, a new temperature and moisture control system was put into service. It replaced the natural “cold spot” of the entrance rubble by an artificial one, condensed the moisture in the air (if too humid) on the batteries to avoid condensation on the walls, and maintained air convection.

From its discovery until its closure twenty-three years later in 1963, Lascaux was adapted for visits and for the physical conservation of its rock art, to the detriment of its archaeological integrity. The closure of the cave ended access to one of the world’s most prestigious prehistoric sites and weakened the local economy, which is closely tied to tourism. The measures put in place and the ensuing relative stability of the cave enabled the commission to authorize restricted visits— 5 people a day, 5 days a week, for 35 minutes—which naturally fell well short of the demand.

Lascaux II, III, and IV

Having acquired the cave in 1972, the French state authorized the Count de la Rochefoucauld to have a life-size replica made near the original. Shortage of funds prevented completion of this project, which was taken over and successfully concluded by the General Council of the Dordogne, aided by the French state. The running of the cave replica was entrusted to the Dordogne tourist board, and then to the semi-public company Semitour. Inaugurated in 1983, this life-size reproduction of part of the cave—the Hall of the Bulls and the Axial Gallery—by local artist Monique Peytral and others is known internationally as Lascaux II.



Entrance to the Lascaux Cave: construction of the vaulted hall of
the first airlock. Standing in the foreground is primary school teacher
Léon Laval, wearing white knee socks. Laval Collection/Fonds Laval.




Longitudinal stratigraphic section of entrance to the Hall of the
Bulls around the time of the discovery in 1940 and after the changes
to make the cave accessible to visitors. © MCC-CNP.










Clay shoulders at the foot of the walls of the Axial Gallery, covered with compresses steeped in fungicide in 2002. © D. Bouchardon-LRMH.


But Lascaux II also proved problematic. Its success—250 000 or so visitors every year—led to the construction of an infrastructure which was supposed to be enlarged in 2003. However, the cave is not a closed environment, and, worried by risks linked to the proposed extension of construction work, the Scientific Committee wanted greater monitoring of the cave’s environment. A commission was created to oversee the coordination of interventions on Lascaux hill. Using the findings of a study showing that Lascaux II’s groundwater basin extended beyond the land initially acquired, the French state began buying up plots from which polluted water was likely to seep into Lascaux.

This was the first step in the plan to turn the Lascaux hill into a kind of sanctuary, the outcome of which will be an ambitious project for an international cave painting center, Lascaux IV (Lascaux III being an international touring exhibition called “Scenes from the Stone Age: The Cave Paintings of Lascaux” in which visitors take a virtual tour of the cave).

Located at Montignac, at the foot of the hill, Lascaux IV, which is slated to open in 2016, will be funded by the French state, the Aquitaine region, and the Dordogne department, and will include a complete life-size replica of the Lascaux cave complex and of all of its paintings (as opposed to the partial replica of Lascaux II), as well as a 3-D reconstruction and interactive displays.

The fungal infestation of 2001

In the 1990s, Jean-Michel Geneste, a curator at Lascaux, noted in his status report Lascaux, état des lieux that equipment set up as a temporary measure during an earlier fungal outbreak was showing signs of wear and tear. One example was the climatic regulation machine installed in 1965. Renovation work on this equipment and on its wooden roofing was entrusted to the chief architect of historic monuments, Philippe Oudin. A new air recirculation system offering more technical possibilities was installed, and further improvements and new equipment brought into service between 2009 and 2011 maintain a wholly satisfactory microclimate within the cave.

Along with this work, an ongoing campaign by the Laboratoire de Recherche des Monuments Historiques to kill lichens in the Hall of the Bulls was entrusted to a restorer specializing in parietal art, in the Spring of 2001. But there was a sudden proliferation of fungi on the floors and benches in the second airlock, at the entrance to the decorated areas, and in the newly equipped machine area. Several factors could explain this unexpected fungal growth: confinement of the cave during the renovation work (an extruded rigid polystyrene foam partition was put up to separate the rock art from the working area), introduction of organic materials, acquired resistance of the microorganisms to biocides used long-term, and upsetting of the balance of the biotope.



Temperature and air flow speed findings
relating to a section in the
Passageway and
the
Mondmilch Gallery, showing the thermic
profiles in September 1981and December
1999. © I2M – Université Bordeaux.



After identification of the culprit fungus, Fusarium solani, the Laboratoire de Recherche des Monuments Historiques proposed a treatment based on quaternary ammonium, applied by spraying or using moistened compresses. As this fungicide is degraded by Pseudomonas fluorescens, a bacterium associated with the fungus, antibiotic is occasionally added to the treatment. But these microorganisms proved particularly resistant and the initial results were unsatisfactory. In October 2001, it was decided to “sterilize” the floor by spreading quicklime, completed by manual elimination of visible microorganisms from undecorated areas. Weekly monitoring was initiated.

In view of the complexity of the problems encountered, the Minister of Culture set up a Scientific Committee of curators, biologists, hydrogeologists, and climatologists, which focused its efforts on finding the source of the contamination and on the structural fragility of the cave. After two years of spot treatments with quaternary ammonium, the contamination by Fusarium was stemmed and there was a marked decrease in fungal growth. The committee drew up a conservation plan and decided to interrupt the biocidal treatments and to favor “mechanical” action on the visible microorganisms. Since 2004, a team of restorers has been monitoring the walls using an analytical chart and by manually eliminating where possible visible microorganisms from undecorated walls. The quicklime that had covered the floor since 2001 was removed under archaeological supervision.

A three-dimensional survey of the cave in 2003 has recently been enriched by the acquisition of data on a submillimeter scale, yielding a model used for georeferencing of observations in the cave. Using this three-dimensional model, a research program called the Lascaux Simulator has improved understanding of the climatological phenomena in the cave and facilitated assessment of perturbations related to air circulation and human presence. Visualization of air flow speeds and temperatures in the Axial Gallery and the Hall of the Bulls revealed that the cold spot located in the upper area in 1981 had shifted to the lower area by 1999. This temperature inversion led to stratification of the air, with a 100-fold reduction in air flow speeds. Multidisciplinary modeling identifies sensitive zones by specifying air and moisture transfers within the cave. The resulting data are always correlated with in situ measurements and human observations. The impact of temperature, humidity, carbon dioxide concentration, and air speed on deterioration of the wall paintings can also be studied using measurements made by probes inside the cave and Lascaux Simulator calculations.



Black stain on the Passageway vault. Photo taken on September
2011 as the phenomenon was being monitored.
© MCC-DRAC Aquitaine.


The black stains of 2006

Faced with difficulties in objective monitoring of the walls, the Scientific Committee asked a team of restorers aided by geologist and a photographer to review the state of the cave. Their status report is still a reference. In the Spring of 2006, new fungi were noted where the substrate, a soft, crumbly limestone, had long been weakened. Black patches appeared on the vault of the Passageway, where there are traces of paintings, but also on the vault of the Apse and Nave which is rich in engravings.

After a test period, the Scientific Committee approved the principle of a biocide treatment, which was applied to the contaminated surfaces in 2008. Measurements of adenosine triphosphate after treatment indicated reduced metabolic activity in nine of the eleven test areas. The treatment, which gave rather satisfying results, was completed by manual elimination of visible microorganisms, outside the decorated zones and under archaeological supervision. By the summer of that year the condition of the Hall of the Bulls and of the Axial Gallery had stabilized well, but contamination persisted in the Passageway, Apse, and Nave, despite regular removal of visible microorganisms.



Graphic representation of the engravings in Area A of the Passageway
in 2008 studied for possible consequences of mechanical
cleaning of black stains. © MCC-CNP.



Disagreement about the relevance of the use of biocides led the Scientific Committee in late 2008 to put in place an impact study before any new intervention. This involved assessment of the efficacy of a biocide treatment combined with manual cleaning, compared with biocide treatment alone, but also the collection of data on the feasibility of such interventions in decorated areas where the limestone is fragile.

Four areas on the vault of the Passageway were selected, depending on the nature of the support (fissures, morphology), their archaeological sensitivity (proximity to engravings, traces of pigments), and visible microorganisms (appearance, thickness, recent changes). Before any intervention, the Centre National de Préhistoire surveyed the decorated area and the restorers in charge of cleaning mapped the substrata to assess the impact of possible mechanical action on the vault of the Passageway and the feasibility of manual intervention. Soft brushes were used to clean the surface of two zones, while two other zones were also treated with biocide. Microbiological analyses were done before and after cleaning, before biocide treatment, and, finally, three weeks after a post-treatment rest period (ATP, epifluorescence, emission spectroscopy, microscopic and molecular analyses, analysis of surface residues from the cleaned surfaces). This study confirmed the need to combine manual cleaning with biocide treatments, but also showed that such intervention irreversibly damages the wall, thus discounting its use on archaeological zones, decorated or not.

Differences of opinion among microbiologists prompted the Scientific Committee to apply the precautionary principle and not use biocides, a ruling that is still in force. Regular monitoring of visible microorganisms since 2007 and tracings and photographs have been used to track microbial growth. Although the appearance of new spots is most unfortunate, the cumulative surveys are nonetheless encouraging. Since treatments were stopped, visible microorganisms have remained in certain sectors, notably on the vault of the Passageway, the Apse, and the Nave, but few new spots have emerged. The color of many patches has faded from black to gray, and the few newly affected areas on the vault of the Passageway and the Nave are usually apparent as pale gray marks or extensions of old blotches in the form of small spots.

Diversified scientific research in the preservation of Lascaux

Following the 2001 fungal infestation, the Scientific Committee launched multidisciplinary research programs to track down the source of the microorganisms and to develop effective monitoring tools. Specialists in microbiology, atmospheric physics, and the transport properties of rocks conducted a study to assess the impact of physical parameters of the atmosphere and substrata on growth of microorganisms. They monitored microbial contamination in three zones at the entrance to the Axial Gallery and correlated changes with physical and microclimatic data recorded at the surface and within the rock substrate. Their findings confirmed the major role played by the microclimate at the surface of walls in microbial growth at the air-mineral substrate interface.

Happily, changes in the microclimate were too small to alter the microbial colonization, which remained largely stable, making it impossible to cross-reference the climatic and microbiological data. At the request of the Scientific Committee, the focus was shifted to the right sector of the cave, at the entrance to the Nave. Two new zones were chosen as a function of the nature of the substrate and the level of microbiological contamination. Here too the climatic stability prevented correlation of the parameters studied, and the program was halted.



The Panel of the Great Black Cow in the Nave. © MCC-CNP.


In parallel, another program on the microbial ecology of the Lascaux Cave was designed to shed light on the microorganisms that cause contamination, by studying their metabolic requirements. Rather than eliminating the apparently dominant species, the aim was to consider all the microbial communities and their equilibria, in an ecosystem approach to the various processes and features of the cave’s biodiversity. In 2011, this research program confirmed the identification of the fungus Scolecobasidium (Ochroconis) in the black spots, but also revealed a new species of Scolecobasidium, called Ochroconis lascauxensis. This study moreover posited the possible role played by the feces of springtails (wingless arthropods) in the dissemination of Scolecobasidium spores. Given the importance of this fine ecosystem approach, it will be continued through a new program, which is currently being drawn up. In 2009, wormlike marks were noted in the Hall of the Bulls. A natural phenomenon observed in other caves in the Dordogne and already seen at Lascaux, these small deposits a few millimeters in size result from the transport of sedimentary particles. Regular photographic monitoring showed that the phenomenon spread slowly. Although such deposits are common underground, the literature on them is sparse. It was therefore decided to appoint a new Scientific Advisory Board, under the presidency of the paleoanthropologist Yves Coppens, to define an appropriate research program.



Wormlike deposits in the Hall of the Bulls. © MCC-DRAC Aquitaine.


A network of specialists undertook a comprehensive study of the geological, geomorphological, and pedological context of the Lascaux Cave, to elucidate the role of the soil-organism system and past and foreseeable changes in the cave ecosystem. The main purpose was to assess the risks related to the local vegetation and to understand transfers from the surface of the plateau to the cave.

Conclusion

We are seeking to minimize perturbation of the fragile, living milieu that is Lascaux, while recognizing that we cannot reverse our heavy-handed interventions since its discovery in 1940. Given the importance of Lascaux in the history of humanity and of art, it was small wonder that the fungal infestations alarmed the scientific community and the public. Nevertheless, the scientific and financial efforts deployed by the State are equal to the task. While we cannot restore the equilibrium procured by the cave’s prolonged isolation, everything has been put in place to stabilize the conditions. The history of Lascaux has highlighted the great vulnerability of this heritage and is a vital contribution to the conservation of similar heritage sites. As curator of the Lascaux Cave, it is my duty to watch over this jewel of prehistory and to ensure it is preserved for future generations. ■

Further readings
– Aujoulat N. Lascaux, le geste, l’espace et le temps. Paris, Le Seuil, 2004, 273 p. (collection “Art rupestre”).
– Bataille G. La Peinture préhistorique. Lascaux, ou la Naissance de l’art. Éditions Skira, 1955, 152 p. (collection “Les grands siècles de la peinture”).
– Breuil H. Lascaux, in : Quatre cents siècles d’Art pariétal, Montignac, CEDP, 1952.
– Leroi-Gourhan. A. Préhistoire de l’art occidental, Paris, Citadelles et Mazenod, 1965, 485 pp. (collection “L’Art et les grandes civilisations; 1”).
– Symposium “Lascaux et la conservation en milieu souterrain,” Actes du symposium international, Paris, 26 et 27 février 2009, dAf 105, Editions de la Maison des sciences de l’homme, Paris 2011, 357 pp.