Nearby rocks
It is its geological history which gives at the Grand Site de France Solutré Pouilly Vergisson its spectacular character. A rare phenomenon in the region, the result of millions of years of evolution, distinguishes the Rocks from the surrounding mountains: made up of resistant elements with a crystalline sub-basement and limestones from the Middle and Upper Jurassic, the ranges are delimited by two tectonic divides: the Saône and Grosne valleys.
The formation of rocks
The rocks, brittle and cracked, are formed of limestone. These are monoclinal ranges characterized by their north – north – east / south – south – west orientation, a steep slope, facing west and a gently sloping side, facing east. To the south, these ranges butt up against the crystalline base of Beaujolais, almost completely free of its sedimentary cover. To the north, they extend into other ranges.
Paleozoic or Primary Era: from 540 to 245 million years ago.
The geological history of the Grand Site de France Solutré Pouilly Vergisson begins 360 to 290 million years ago. At the end of the Primary Era, at Carboniferous, is formed, by erosion of the Hercynian folding, the base of the Mâconnais mountains, presenting a slightly bumpy plateau landscape.
Mesozoic or Secondary Era: 245 to 65 million years ago
200 million years ago, during the great period of marine sedimentation, Burgundy is covered by a warm sea, the Tethys. During all periods of the Jurassic, different limestone layers are formed. These layers trap debris of molluscs, shells, crinoids and other marine animals, many of which are found today fossil clearly visible. They form marl, a sedimentary rock found mainly at the foot of the rocks, a sign of a warm climate and shallow seas, conducive to the development of significant underwater life.
Au Jurassic medium, 150 million years ago, the reliefs of Vergisson and Solutré were formed and covered with corals (formation of a coral reef, comparable to those of the current South Seas). The sediments are named after polystone limestones. They are very resistant to erosion and are found today on the summit of the Roches.
Between 150 and 130 million years ago, during the Lower Jurassic, fairly soft limestone layers were formed, on which during the Cretaceous, between 130 and 65 million years ago, a layer was deposited chalky very fine. Around 70 million years ago, the sea gradually retreated. A long phase of erosion removes upper layers of sediment.
Cenozoic or Tertiary Era: 65 to 1,65 million years ago
Around 30 million years ago, eastern Burgundy, particularly the Mâconnais, suffered the impact of uprising of the Alps. The land fractures in the main North–North-East/South–South-East direction. The Saône basin collapsed, giving rise to the Bresse. To the west, present-day Mâconnais, plateaus rise then tilt towards the east forming the line of Solutré – Vergisson – Montsard cuestas. Cretaceous sediments are washed away.
Acceleration of the erosion process
The formation of flaws brought together, side by side, terrains of different nature and resistance. 650 years ago, the first glaciations began, which lasted until around – 000 years ago. The slopes undergo a erosion particular to each glacial episode that the region experiences. The watercourses being unable to evacuate them towards the Saône, the materials constituting the slopes accumulate at the foot of the cornices after being burst by the frost. The current topography of the cliffs, with angular contours, bears witness to these different erosions. These continue, quite slowly, to sculpt this landscape that we know today, favored by the cultivation of the slopes.
