Geology – Stratovolcanoes in Mandelieu!
The Mandolocian scene is revealed with its jagged coastline, its plain where a river flows and its polychrome mountains. It was established almost 340 million years ago, at the time of metamorphic rocks such as gneiss and granite, which formed the base of what was once an immense Hercynian chain nearly 3 kilometers long. Here we contemplate a magnificent survivor, the Tanneron massif, although today it is very largely eroded.
The next stage in the formation of the contemporary landscape dates back to the Carboniferous period, 30 million years later, during which the Earth's crust cracked, creating rifts – faults – where lakes and marshes formed. The tropical climate of the time led to the development of forests that would later fossilize in the form of coal and oil shale.
In the geological period that followed, the Permian, the continental crust stretched, leading to a universal thinning which, at certain weakened points, caused a massive and explosive magmatic upwelling over a long cycle of almost 30 million years. She is at the origin of the EsterelThe blood-red splendor that characterizes this massif is due to the rhyolites expelled in this outburst of extreme violence. Other rhyolites also ejected here, in smaller quantities, present more pastel shades of blue, green or light gray.
Volcanoes in number
It would take another 70 million years for a new phase of explosive volcanism to occur, producing stratovolcanoes. Mount Vinegar which rises to an altitude of 618 meters in the heart of the Esterel, is the perfect example as well as the caldera – from the Portuguese meaning cauldron – of Old MaureThe latter, with a diameter of some two kilometers, is due to the collapse of a stratovolcano, which generated a vast flat-bottomed depression punctuated by a few necks of trachyte. Another 20 million years later and it is the cone of San Peyre which in turn arises. The Hanging Rocks, on the seaside, come from the same volcanic phase as the latter. And another 10 million years are needed for cooling to lead to the formation of rhyolite organs – columnar prisms – visible in particular at Mont Vinaigre.
In short, it took millions of years for this scene to emerge, which owes almost everything to volcanism and the erosion that followed.
Today, the whole area is covered with dense forests and scrubland, which give the area one of its main attractions and make Mandelieu La Napoule the greenest town on the Côte d'Azur.
