The sandstone of Annot

 Sand avalanches under the sea

A link in the history of the Alps…. 

The collision of the continental blocks of Europe (Eurasia) and Apulia (north of Africa), which began around -35 million years ago, continues. The alpine reliefs develop in the east, at the current location of northern Italy. The sea which borders the nascent Alpine chain, to the west and to the north, gradually deepens due to the movements of the continental crust resulting from the collision. Erosion attacks the emerged massifs and causes more and more deposits towards the sea, until it is filled.

Around -35 million years ago, the seabed experienced the deposit of nummulitic limestones. They were then enriched in clays, then, gradually, in more and more abundant sands. These sands are transformed into a hard rock, sandstones, by cementing the grains together, thanks to a binder whose composition can vary (limestone, siliceous, clay, etc.).

This succession of limestones, marls and sandstones is qualified as a 'trilogy' by geologists and reflects the history of this sea.

The Grès d'Annot originated in this sea during its filling (phase 3 of the 'trilogy', between -34 and -30 million years ago). These sandstones bear the name of the locality where they were described by geologists. If they are particularly well represented and accessible around the village of Annot, they actually occupy a very wide geographical distribution, from the Estrop massif in the north-west, to the south of Mercantour (Peira-Cava).

The appearance of the sandstone layers, their organization between them, their thickness, the organization of the grains, the geometry of the deposits are all information that allows geologists to understand the placement of these masses of sand.

Thus, the layers of Annot sandstone have been interpreted as massive arrivals of sands at the bottom of the sea by a process of underwater avalanches. The sands (and other materials, clays, pebbles, gravel…), resulting from the erosion of the continental reliefs have accumulated in the areas of coastal slopes.

Remember that at the time, the tectonic context was active, earthquakes were frequent. The sandy slopes shaken by these earthquakes are subject to massive landslides. Sandy packets are carried away and set in motion in the water, in the form of avalanches. The height of the water section, the topography of the bottom, the mass set in motion, the size of the grains transported, are all factors that will influence the size and organization of the sedimentary body that takes place downstream.

A sandstone bank has, classically, the largest elements at its base (pebbles, gravel), then gradually, upwards, increasingly fine sands take place and, finally, clays. Each such stratum can be several meters thick. It is the result of a single event, in short, ephemeral.

But where do all these sands come from?

From the source zone downstream, the layers of sandstone lose thickness and spread out in fans over kilometers away. The organization of the deposits shows that the source of the material is located towards the south-east, and the composition of the grains of sand reveals that the rocks subjected to erosion strongly resemble those of Corsica!

Today, this source area has disappeared. Between -40 and -30 million years ago, the Pyrenean-Provençal, or Pyrenean-Corso-Sardinian mountain chain, in the process of erosion, existed at the current location of the Mediterranean Sea. Rivers carried northward, that is to say, to the sea at the time, the products of erosion found in the Grès d'Annot.

From that time to today, the landscape has completely changed!

... in connection with Eaux-Tortes and Lac d'Allos

The Annot sandstones form the remarkable sedimentary pile which crowns the Estrop massif and its summit (2961 m). From there, the large sandstone slabs plunge towards the Blanche de Laverq valley. The Blanche glacier has carved out the depressions, now peaty, of the Eaux Tortes in these sandstones. At Lac d'Allos, the magnificent ruiniform towers are also carved in the sandstones of Annot.

 The legend of the king's bedroom

The great sandstone cliffs and the immense rocks hollowed out and sculpted by erosion or scattered perhaps by the collapse which once created this chaos, must have, certainly, for many, have helped the popular imagination and the birth of legends which are numerous in the “Pays d'Annot”, the most popular being that of the King's Chamber.

This happened at a time when the centuries still had only one number… It was still a time when the Saracens who roamed Basse-Provence sometimes managed to make brief forays into our regions… Sigummana was the old name of Annot, when our distant ancestors, formed as a tribe, lived in the district of Vers-la-Ville, has always been faithful to the Catholic faith and to the Roman Church. Also, one day in the 9th century, a Christian Lord of Basse-Provence, accompanied by his gentle princess and some vassals, pursued by a horde of infidels, asked for asylum from the Lord of Sigummana, Hermérincus.

Having obtained it, he was granted as supreme refuge, a cave at the end of the rocky bar, overlooking the valleys where the waters of the Vaïre and the Coulomp mingle.

This cave is located at the entrance of a natural rocky cirque, the narrow passage of which, by means of branches and rocks, allows to conceal it, making it possible to keep this hiding place secret from invaders.

The Saracens searched in vain for traces of our proteges, withdrew, but promised eternity to find them.

Our hosts thus lived for a while under our sky, sharing our customs and manners from then on, before a traitor came to reveal the hiding place to some heretical emissary.

The next day, the infidels returned in number, discovered the royal lair and put to death the prince, his loving companion and all their Court; they were finally thrown into the void of the supreme rocky outcrop called from "the King's balcony".

They only had time to complete their crime, which they scattered in Sigummana, to slay the unfortunate inhabitants, accomplices according to them, to have given refuge to their enemies. It was then that, saving our ancestors from a slaughter, the plague broke out in the ranks of the Saracens; those of them who were not yet affected would have fled before putting their project into execution ... It is also said that the epidemic would have stopped, as if by a miracle ...

It is since this time that this cave and the district have taken the name of "King's Chamber"; we also find the "King's Gardens" ...