G for Cave

Definition

Generic name of a cavity, flooded or not. Parietal cave, freshwater, marine, lava, of ice: cave diving, in all its variety, has become synonymous with cave diving. 

Synonymes

Cave | Cavity | Tunnel | Anfractuosity | Awning | Rock shelter | Hole | Cellar | Cueva | Höhle ...

Starter

This cave is either filled with fresh water, an underground river submerged under pressure, subject to currents or, in the case that interests us, sea water, this time the seat of the surf, another alternative and salty form of the current ... What more basic than a “cave”? We all know that there is sometimes eel under rock and even, most often (it is one of the cradles of humanity) shelter under rock. The valley of the Dordogne account quantity of these “shelters”, overhangs formed along the rivers during old river levels, of often modest developments, their speleological interest being inversely proportional to their archaeological interest. Because our grandfathers lived in these shelters, protecting their rear, with a view of the horizon. The first taggers were also rife in the caves ... But let us leave there these “caves” and other chantoirs of limestone soils, these caves, these chasms, these abysses, these springs, fountains and other drowned networks, playground for speleonauts for other caves better known to the swarms of divers “in sea ​​”: the sea caves, filled with sea water, which often open flush with the water, in the side of our coastal massifs. But sometimes also in depth, like the famous Cosquer cave. 

It all depends on their origins or, to put it mildly, on their speleogenesis. Either they are old “karst” caves hollowed out by the action of fresh water, then exposed, then finally flooded with seawater when seawater rises during the last deglaciations (+ 150m in the Mediterranean ) such as the aforementioned Cosquer cave, for example, but also the Hopper cave in the creeks of Cassis, or the sea caves of Capo Caccia in Sardaigne, the exploration of which was told in my book narcosis. This also applies to the blue holes in the Bahamas or the family Belize, or cenotes of the Mexico they are often re-drowned in superficial fresh water.

Main course

Either they are authentic sea caves, carved out by the sea on the coast, often thanks to a fault in the rock. This explains why they are often fairly simple in shape and poorly developed, due to their success with scuba divers who appreciate their apparent “ease” while enjoying the thrill of earth-diving. An entrance leading to a short tunnel often followed by an ascent in the open air or a crossing: almost every dive site in the world has “its” cave, abundantly frequented, unfortunately with “standard” diving equipment, which is in most cases largely underestimated and even “accident-causing” and above all guided by the “owner” of the premises who knows it “by heart”…

In fact, any diving “under the ceiling” should only be undertaken by divers who have received an initiation and training in cave diving, with suitable equipment (redundancy of air and light sources, among others) and techniques. specific (air stock management, use of the guide wire, blind progression). The apparent simplicity of the topography of these caves often hides traps that can be fatal.

This topography depends mainly on the rock where they are established. In granite, as in Lavezzi in Corsica or on the north coast of Britain for example, it is often chaos of blocks and enormous pebbles determining in their stacking of short tunnels and crossings which it is pleasant to frequent.

We know of other sea caves in the schist, which develop to a cul de sac, often in a straight line in the extension of an inclined fault as in Morgat, in Brittany. Ditto at the limestone coast where the erosive force of the sea always starts again. We also know these caves in the sandstones, like those of Trayas Mediterranean coasts, and even in the conglomerate, including the caves that cross the massif of the eagle in Figuerolles near La Ciotat, like Gaméou's lair (see the video) are a good example of complexity.

 

 

It is also found in basalt such as the Buracona cave on the island of Sal au Cape Verde, lava tunnel cooled and flooded with salt water. But also and especially within the coral massifs, piles on considerable thicknesses of living beings which will transform later into limestone rock, coral which often spares fantastic canyons and caves sometimes of very large size and of respectable development as in the platiersRodrigues Island in the Indian Ocean or in the flower beds of the Fury Shoals in the Red Sea…

Smashed on the walls

Apart from the classic carelessness committed in these deceptively good-natured sea caves, there are dangers that we do not necessarily think of. The profile of the dive first, often ending up on the surface in some decorated bell and sometimes preventing the return, as we explained in the article on the maneuver of the valsalva. But also the swell and the surf, kind of currents for which we are very little prepared underground ...

South Australia. We dive to the edge of the land, from a reef of coralligenous that directly overlooks the deep blue of the Pacific. A vertical and scoriaceous drop off which will be found emerged by the tide at the end of the dive, forming for kilometers a cliff of several meters, black, sharp and dripping, practically impassable. But this is another story… For the moment we are swimming askew, from left to right, as the large algae coils up before the movement is reversed. Deep red, fluorescent green, all the browns, moss plants of all shapes and colors where so many species hide that we had never seen: “blue devil”, a kind of blue grouper spotted with purple at the entrance of his hole; square mouth of the sharks “Port Jackson”; mimicry and camouflage of the cashmere-dressed “Wobbeegong sharks”, winding on the shell sand amidst orange scallops and black abalone.

Towards the end of the dive we spot in the submerged cliff the black mouth of a tempting cave and we engage without hesitation. There is still air. Just enough for a little reconnaissance while respecting the security reserves. I pull a new thread between the scoriaceous walls, in the darkening blue. The ground is a river of white sand, streaked with dunes. Loose red algae balls float back and forth, silent metronomes. We follow the conduit on the left, then it veers to the right, decreasing by half in size… Protected by the cave, we no longer feel this annoying swell which was sweeping us so outside. And suddenly, it's like a cannon shot: we are rushed forward, bouncing off the walls, tumbling for meters in the middle of the volutes of sand while the pressure on the eardrums becomes unbearable. My head is spinning, I let go of the reel… And we set off again in the other direction, holding on as best we can to avoid further damage before another detonation and everything starts again. Have we crossed another gallery where the ocean rushes in fury? Does the Venturi effect due to the narrowing of the duct have something to do with it? More probably it is about rogue waves hidden in this long swell of the Pacific, come to finish their course in this cavity where we imprudently entered ...

We lack space here to explain how we managed to escape the trap; at most we will borrow the famous formula of the soap operas of the 19th century (whose hero found himself chained, handcuffed, drowned under a hundred feet of water and ice in a case full of poisonous snakes… before “the continuation to the next number”) : “When we got out of this mess… we continued our adventures, as if nothing had happened”. All kidding aside, this problem of swell in sea caves is to be taken very seriously and it has already claimed the lives of several divers engaged in underwater caves in California and that we found smashed on the walls of the duct ...

Dessert

Almost all of our coasts and inlets have their “blue grotto”. In Spain, riding a Greece, riding a Sardaigne and until New Caledonia, they enchant their adventurous visitors. It is therefore very difficult to define “the most beautiful” or “the most famous”. As for the first explorations, I would not be surprised that it dates back to the Neanderthals or even well before, as man has the virus of exploration tied to his body. The most famous in any case and which has crossed and inspired history is the famous blue cave of the Italian island of Capri (no, it's not over ...)

It was used as a private swimming pool and marine temple by the Emperor Tiberius of ancient Rome from 27 BC. At that time it was decorated with statues and set with rest benches. It was in 1964 that three statues of Roman sea gods were found under the turquoise waters: Neptunes and Tritons exhibited at the museum ofAnacapri. But it remains to discover at least four since in 2009 we updated seven bases of the said statues… It was first described by Pliny the Elder then was rediscovered and exploited for the public in 1826 and immediately met with great success. You entered it by boat through a low window opening into a blue nave, dazzling with the chilled sun. Romantic place that inspired painters, musicians and even writers: The great Mark Twain he himself visited the cave in 1869 and told it in his book “The journey of the innocents”…

See you soon for a new definition of Scuba Bécédaire. The irreverent lexicon of diving, but not only. Because sometimes ...

Francis Le Guen

 

 

Café

A fine example of a sea cave: crossing the cave of Gaméou in the Calanque de Figuerolles at La Ciotat : it's next to ! Finally, it all depends on where we start ...

And then, bonus, as the name suggests. Because we love caves. And women. Or the opposite. Or both. In short !