Nearby rocks
It is its geological history that gives 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 Roches from the surrounding mountains: made up of resistant elements with a crystalline basement and limestones from the middle and upper Jurassic, the ranges are delimited by two tectonic trenches: the valleys of the Saône and the Grosne.
The formation of rocks
The brittle, fissured rocks are formed of limestone . They are monoclinal ridges characterized by their north-northeast/south-southwest orientation, with a steep westward-facing slope and a gently sloping eastward flank. To the south, these ridges abut the crystalline basement of the Beaujolais region, almost completely stripped of its sedimentary cover. To the north, they extend into other ridges.
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, in the Carboniferous period , the base of the Mâconnais mountains was formed by erosion of the Hercynian folding, presenting a gently rolling plateau landscape.
Mesozoic or Secondary Era: 245 to 65 million years ago
200 million years ago, during the great period of marine sedimentation , Burgundy was covered by a warm sea, the Tethys. Throughout the Jurassic period, different layers of limestone formed. These layers trapped the remains of mollusks, shells, crinoids, and other marine animals, whose numerous fossils are still clearly visible today. They form marl, a sedimentary rock found mainly at the base of cliffs, a sign of a warm climate and shallow seas, conducive to the development of abundant marine 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 region, was impacted by the uplift of the Alps. The terrain fractured along a main north-northeast/south-southeast direction. The Saône basin collapsed, giving rise to the Bresse region. To the west, in what is now the Mâconnais, plateaus rose and then tilted eastward, forming the Solutré-Vergisson-Montsard cuesta line. The Cretaceous sediments were leached away.
Acceleration of the erosion process
The formation of faults brought together, side by side, terrains of different natures and resistances. The first ice ages began 650,000 years ago and lasted until around 10,000 BC. The slopes underwent specific erosion with each glacial period in the region. Since the streams were unable to carry the material to the Saône River, the materials that made up the slopes accumulated at the foot of the cliffs after being fractured by frost. The current topography of the cliffs, with their angular contours, bears witness to these various erosion processes. These processes continue, rather slowly, to sculpt the landscape we know today, a transformation facilitated by the cultivation of the slopes.
