The Race to Document Prehistoric Art in a Coastal Cave in

When prehistoric artists entered the slender initially passageway of what is now Cosquer Cave some 27,000 decades in the past, they moved from flat, grassy plains up a tiny incline to the base of a cliff a couple of miles from the sea. Currently, when Bertrand Chazaly enters the French cave to digitally scan the paintings and engravings all those artists developed, he has a tougher journey.

Increased sea levels since the final ice age have still left the cave’s mouth additional than 120 ft underwater, and submerged the tunnel, which is longer than a football subject. But at its end are two chambers that are at least partially dry—for now.

Cosquer Cave incorporates a trove of prehistoric artwork, but its inaccessibility tends to make it complicated to analyze. And the clock is ticking: Encroaching sea stages are washing absent paintings and engravings. The 3D electronic styles Chazaly’s team generates will maintain the internet site nearly, but accumulating knowledge will take specialized innovation and physical endurance.

“It’s really difficult,” states Chazaly, a land surveying engineer who specializes in caving and cultural heritage for geo-knowledge enterprise Fugro. Over the previous 12 several years, he has labored various months each and every year in the cave. “It’s actually a problem of enthusiasm.”

This year, Chazaly’s team completed mapping the portions of the cave that are higher than water, utilizing laser scanning and photogrammetry to create styles accurate to inside .1 mm. Future, they’ll doc what’s underwater. However no artwork survives on the submerged partitions, a comprehensive product of the cave technique will support scientists understand how it was used in prehistory.

The cave’s remaining artwork, dated to in between 19,000 and 27,000 years in the past, consists of hand stencils by adult men, females, and kids, and scores of animal figures: bison, horses, ibex, and chamois, as perfectly as seals and seabirds.

Today, the entrance to Cosquer Cave is more than 120 feet underwater, at the base of this cliff.
Currently, the entrance to Cosquer Cave is additional than 120 feet underwater, at the base of this cliff. Georges Seguin (Okki), CC BY-SA 3./Wikimedia

Prehistorian Jean Clottes was doing the job at the French Ministry of Culture in 1991 when diver Henri Cosquer claimed a cave he experienced learned a couple of years earlier on the rocky coastline east of Marseille. Cosquer’s photos intrigued Clottes, but he could not see it for himself—he wasn’t a diver. Even now, it usually takes a unique skill established, combining abilities in both equally cave art and cave diving, to study Cosquer in man or woman. “There are not way too lots of people today who can do that,” Clottes suggests.

Clottes ultimately became one of individuals people today, mastering to dive at age 69, just so he could analyze Cosquer Cave. He’s manufactured dozens of visits and, the moment he reaches the cave’s dry chambers, states his do the job is equivalent to other prehistoric websites. But just obtaining to the cave can be intricate rough seas and terrible temperature often terminate outings.

Cosquer presented one of a kind difficulties even for Chazaly, who has worked in some serious areas, such as the spire of Mont-Saint-Michel, 450 meters underground in nuclear waste storage galleries, and the Good Hypostyle Hall of Egypt’s Karnak Temple. When the French Ministry of Society to start with contacted him additional than a 10 years ago about the likelihood of building a digital product of Cosquer Cave, Chazaly initially needed to strengthen his diving expertise, from leisure to experienced level. It then took many a long time of exam visits just before his workforce could commence to scan the cave in 2017.

Each and every scanning journey includes one or two researchers accompanied by two skilled divers who are common with the cave. From a boat off the rocky coastline of Calanques Countrywide Park, they descend into turquoise Mediterranean waters, carrying tools in sealed luggage and a vital to unlock the gate at the tunnel’s entrance.

A cross-section of Cosquer Cave today as water levels continue to rise in both chambers.
A cross-part of Cosquer Cave now as water degrees carry on to increase in each chambers. Courtesy Bertrand Chazaly

With one particular diver at the front and 1 at the again, they swim slowly, mindful not to kick the sediment on the floor which, if disturbed, dangerously clouds the water. In 1991, a few divers died following getting to be disoriented by sediment swirling by the passageway. Now, a lifeline extends the tunnel’s duration.

Soon after about 15 minutes, the team climbs onto la plage, the beach, exactly where they depart their diving equipment to work previously mentioned drinking water stage on slippery flooring amid stalagmites and stalactites. No subject the year, Chazaly states, the temperature is usually about 64 degrees Fahrenheit.

Within, there are stringent principles. They must not touch the fragile walls. The only sustenance allowed is water. Through their hours-very long keep, they simply cannot snack. They just can’t pee. “You genuinely have to be organized,” suggests Chazaly. “Sometimes you are seriously in a hurry to get out of the cave.”

Chazaly’s team custom-made a laser scanner for the cave’s very low-mild, distant setting. While the scanner information 70 million details in three minutes, positioning the device—and the humans—took a lot of time. Through each individual scan, the staff hid so they would not look in the information. At moments, colleagues bodily held Chazaly on a precarious location of dry ground. Often he stood upper body deep in drinking water with the unit on a tripod. Twice, scanners fell into the water and ended up wrecked.

Chazaly (left) and another team member discuss how best to position scanners and other equipment in a partially-submerged chamber.
Chazaly (remaining) and a further workforce member talk about how finest to posture scanners and other machines in a partly-submerged chamber. © Luc Vanrell–Immadras/courtesy Bertrand Chazaly

When scanning each individual dry cranny of the cave, the lights illuminated new specifics. Chazaly recollects a single time when an archaeologist with the group exclaimed, “Look right here, there is a small horse!”

“Nearly 30 decades just after the discovery, just locating a new engraving or something is very strange,” he suggests, “but it took place.”

This year, when Chazaly’s staff starts documenting submerged components of the cave, like some by no means right before explored, there will be new challenges. Divers will expend longer intervals of time underwater, which includes greater actual physical hazard. The team will want to go diving gear as a result of a slim passage amongst chambers alternatively than leaving it at the water’s edge, all devoid of touching the conveniently-broken walls. To document the very long tunnel entrance, where it is not possible to cease due to the fact of the threat of disturbing the sediment, Chazaly’s workforce has created a ring-like array of cameras and lights that will record 360-diploma pictures alongside the way.

Experts familiar with the internet site see terrific worth in a digital replica of the cave, “a bubble of memory shed below the sea,” according to geologist and prehistorian Jacques Collina-Girard, who claims his visits to the cave in the 1990s felt like an H.G. Wells or Arthur Conan Doyle adventure. Currently, the previously mentioned-drinking water scans have been utilized to construct a reproduction of the cave for Marseille’s new Cosquer Méditerranée museum. The digital product, Collina-Girard states, will make the cave available to the community and to researchers from afar, and preserves what the sea will quickly assert.

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