Morphology and geology

Mont Blanc, point of contact between the European and the African plates

Mont Blanc extends from north-east to south-west in the north-western Alpine chain. It therefore evolves in complete harmony with the current direction of the internal powers of the Planet, that tend to bring the European plate closer to the African one, the latter represented by the Padana Plain. Mont Blanc therefore lengthens following the contact points of the continental plates. Its isolation derives from the fact that it rises in the middle of a region with prevailing subsidence. At the feet of the mountain, towards the Valle d'Aosta (Aosta Valley), is the underground sloped plain that caused the European plate to submerge under the Alpine chain. Towards Savoie the European continental crust folds like a mat when it slides against an obstacle. Pushed on its shoulders by the Aiguilles Rouges and blocked behind Mont Blanc, the Chamonix valley narrows following this disforming model.

Its diversity from the surrounding relief comes from the material it is made of. Its rock was formed from a bubble of magma in the overheated bowels of a continental plate. Even though a network of fractures runs through it, the massif maintains the cohesion of a rigid block. Answering the internal stress of the system, it did not crumble or fold like the sedimentary rocks around it, but only took on an almond shape.

The massif rocks

The rocks of a continental plate are often very old and/or recycled. In the European plate, Mont Blanc, which is made essentially from a nucleus of granite enveloped in gneiss, is no exception.

The Gneiss of the external shell derives from antique sedimentary rocks that deformed and rebalanced during the Palaeozoic period (from approx. 542 to 251 million years ago). This shell is preserved in the south-western part of the massif, starting from the top peak towards Aiguille des Glaciers and beyond, and also at the bottom of the Savoie and Vallesano side.

The rocks are crystalline and foliated, made essentially of quartz and feldspar, darkened here and there by higher concentrations of iron and magnesium.

During the Carboniferous period (310 million years ago), a large part of this material overheated and melted. It subsequently cooled, creating a granite nucleus made of quartz, feldspar (at times large white potassic crystals with a rectangular section) and black mica, replaced here and there by greenish chlorite. In the same manner as the gneiss, the granite is marked by darker nodules, and is also intersected by clear threads made up of small feldspar crystals. Contact with the encasing gneiss can be identified halfway down the Savoie face at the height of Montenvers, and in Val Veny along the crest of Brouillard where it takes on the aspect of a brownish festoon.

The shapes

The part of Mont Blanc that is still protected by a gneiss shell presents more rounded and continuous shapes on which the normal roads for the peak have been traced. Where the granite appears on the surface, however, the relief is quite marked by fissures produced during the strain of rising. These fractures limit the pillars, spires and towers that have made the massif famous.

Massif rise and finishing

Around twenty million years ago the European plate met the African one, and ended up being submerged by the alpine plate that was, and still is, positioned between them. The rise of Mont Blanc began when the massif, which was inside the European plate, found itself on the edge of the immersion face. As a result of its size and relative lightness, it was undermined and pushed to the surface on the edge of the furrow, against the slopes of the alpine chain.

Inside the plate where Mont Blanc was (and still is, in part) buried, up to the 4807 m of its peak, the massif absorbed an enormous quantity of energy and heated somewhat, making fluids full of silica run into the fissures created by deformation. The treasures of the Savoie and Valdostana "cristalliers", the magnificent druses of quartz exposed at Chamonix, at Pointe Helbronner and in many world mineralogical museums were created by the slow crystallisation of these fluids.

While it was rising, Mont Blanc underwent various cycles of glacial accumulation on its peak and all the surrounding territory, up to the distant plains. Glacial cirques, thresholds and deep valleys were sculpted into its rock, large valleys deepened into the soft surrounding rocks. The large glaciers took the road of the deep depressions that already existed in this part of the Alps: the Rhone through Savoie, Lake Geneva through Vallese, the Padana Plain through the sloping gulley of the Dora Baltea. Immense quantities of rock and lime were torn from the mountain and deposited at the outlet in the plain; all the rocks along the run of the glacier were smoothed as can be seen today in the more solid and steady stretches of mountainside. The first alpine glaciations began 1.6 million years ago, while the current withdrawal has been lasting for just 10,000 years with some fluctuation. The last sensitive progress on the whole massif is dated 1820, followed by an almost continuous retreat.

Looking around Mont Blanc

The continental European basement (gneiss, mica schist, locally granite) and the sedimentary covering (marl, sandstone, Mesozoic limestone) make up the Savoie territory. To the south of Saint-Gervais the river digs through the covering formations until it discovers the basement that rises from Contamines at Prarion. At times the start of the carboniferous sedimentation is well exposed (Porménaz). The basement, however, which was pushed upwards by the recent (less than 20 million years) deformations of the European plate, appears above all in height: in addition to Mont Blanc, naturally, also in the Aiguilles Rouges, on the peaks of which remain shreds of sedimentary covering. The plate dominates in the rest of the alpine and pre-alpine Haute-Savoie, frequently in overlapping layers even from quite far away (Chablais).

The Swiss sector is divided between the European plate to the west and the metamorphic alpine layers on the east.

The latter are detached parts of various subsided layers, that were transformed and re-emerged during the alpine orogenesis. The Penninic Thrustfront, which marks the contact between these two geological worlds, follows Val Ferret and reaches the valleys of the Rhone towards Sion, not very visible on the surface.

From the European side the basement, softened in relief by the Quaternary glacier and cut by the Rhone, is exposed around Martigny. Mont Chemin, famous for its mines, is an extension of Mont Blanc. The carboniferous covering rises in the valleys of Trient and in the Eau Noire. The upper, therefore most recent (Mesozoic), layers closely follow the gulley that reaches Chamonix. More to the West, the Mesozoic covering appears at the Emosson lakes where the famous dinosaur prints were discovered.

Along Val Ferret and Val Veny the Mesozoic covering is detached, overturned and leaning almost vertically against the granite rock of Mont Blanc. A little more to the east, the Penninic Thrustfront materialises in a series of chalk white flows and black carbon schist that run along the bottom of Val Sapin and cross Chécrouit up to Val Veny. Beyond the Penninic Thrustfront, the metamorphic alpine layers can be seen initially by their muddy detritus, accumulated in this area that were low (Mont Blanc was not yet present) at the feet of the oldest Alps. Mud and gravel have now become schist gaps with limestone, mica and quartz (Licony, Crammont...).

More to the east, the low valleys of Drance and Dora in Valdigne intercept the slopes of the Great St. Bernard, with their black carbon schists that incorporate white crystalline bodies.

Territory and population

The economy and traditions

The country that extends to the feet of Mont Blanc has known, and in part maintained, an alpine culture that is at the basis of the cultural identity of the populations that currently live in it. It is the result of a long common history that the frontiers could not cancel completely. This culture became critical with the industrial revolution and the resulting social-economic upheaval. Great changes occurred at the start of the 20th Century in Savoie, a little later in Vallese and, after the Second World War, in the Valle d'Aosta. In this ancestral society, agriculture was the main occupation: the production of food that had to supply the necessary requirements for survival and, if possible, something extra for purchasing the essential things that did not come from the soil, such as salt. The mountain dwellers, working hard and doing everything possible, were able to manage the territory without disturbing the balance, and organise their life in such a way as to make the most of the agricultural potential, in reality rather reduced.

Rearing cattle was the main resource, the one which made it possible at times to earn the money needed to face special expenses, thanks to the sale of butter and cheese. Cereal growing followed, for bread baked once a year but only for the rich, then vines, a decoration for the sunny hillocks, from which rather sour wine was obtained for feast days or for the summer, when the agricultural work became much harder and the days in the fields became long. Fruit, above all chestnuts, were dried and ground to become flour, but also medlars that were ripened on straw;  apples and pears were grown that could be preserved for winter;  thanks to the oil produced, walnuts and almonds were used to dress food, to light lamps and as a cure for some illnesses; plums, cherries, peaches and apricots, too perishable, were a rather exotic luxury that not everyone could allow themselves.

Wool, hemp, leather and more rarely linen, were used to make clothes. The women spun and knitted and during winter the men generally wove. Pigs, chickens, and at times bees, contributed in varying the family food resources. In spite of the harshness of the places, the people moved, mainly through the hills, to emigrate temporarily during the cold season when there was very little work to be done in the mountains. The mountain dwellers became travelling salesmen, chimney sweepers, hemp combers, trunk sawers and even teachers with two feathers in their hat when they could teach reading and writing, and three when they could also teach arithmetic. They also moved for business reasons: the people from Valle d'Aosta purchased cheese in Vallese and then resold it in Piedmont, the inhabitants of Vallese bought red wine that was rare in their territory and sold it in Valle d'Aosta and Savoie, the inhabitants of Savoie resold salt to the people from Valle d'Aosta, essential for preserving food and for rearing, and they also purchased rice coming from the Padana plain.

Agriculture went into a deep crisis that reduced the sector workers by at least 5%. It was, however, able to concentrate on quality and even if the cereals have disappeared, vines have prospered: Fendant from Vallese, Morgex White from the Valle d'Aosta and the cru wines (wines from specific growth places) from the low valleys of the Arve have transformed and become  sought-after products. Their production is in full development. Even the mountain pastures show good return and products such as Fontina from Valle d'Aosta, Bagnes from Vallese and Beaufort from Savoie have an increasing market: different cheeses, but all, at least as far as origin is concerned, produced on the mountain pastures using fresh milk and following the same techniques.

The breeders, less numerous but with more important animals, always carry out their work passionately and tremble in the face of the exploits of their queen. Cow fighting is an ordinary and natural event when going up to the mountain pastures, where the cows confront each other to establish the hierarchy in the herd, and is now a carefully organised periodic event that crowns the queen of queens at the end of the season. Even artisan work has undergone a profound transformation, but in spite of this some traditional activities have survived and prosper: wood sculpting still exists, above all in Valle d'Aosta, where the Sant'Orso exhibition, held on 30 and 31 January, draws thousands of visitors from the towns and villages that surround Mont Blanc;  in Chamonix, Bagnes and Etroubles  they still produce cow bells, a decoration worn by these animals and a passion of cowherds; herbalists are becoming more popular with an increase in the search for alternative medicine; poor and rustic home cooking has been transformed into a culinary art and old recipes, for example those with a cheese base, are today served in restaurants: raclette,  fondue, valpellenentse.

Even industry, above all big, entered a crisis during the mid-seventies and only the highly specialised small companies in the Arve valley in low Valle d'Aosta continue their activity. It is now the tertiary sector, tourism and business above all, that guarantees the money necessary for the Mont Blanc population.

With the generalisation of sport, the mountain was transformed into an immense stadium for excursionists, skiers, mountain climbers and, during these last few years, those who do those numerous new sports connected with water, rocks, air or snow. Becoming fashionable, it also welcomed those who did not have any special interests, those who simply followed fashion and searched for the same commodities and same enjoyment in the mountains as they would find in the city. In short, for a long time the mountain did nothing more than adapt itself to the changing requirements of the urban population and often of the mountain dwellers, who welcomed new models and hid antique traditions as if ashamed of them. During this last period, fortunately, a new sensitivity arose and continually more tourists became interested in the people from the Alps, and in "the intimate history of the valleys" which goes beyond the standardised folklore and which is of dubious origin. This evolution encouraged the mountain dwellers to think again about their own history, to discover places, moments and activities, to propose them to tourists with a sliver of pride rediscovered. They realised, in this manner, that many things had been forgotten. The mountain dwellers, once held as being wild but kind people or idiots from the Alps, became members of a complex, authentic and original society, worthy of being recognised and understood more thoroughly. A whole new series of initiatives therefore bloomed to reunite, organise and present to the public a precious inheritance that had been lost: the restoration of antique buildings of artistic, historical or ethnographic interest; the collection of objects of material culture to be displayed in local museums; public demonstrations of ancient knowledge; the relaunching of popular holidays (descent from the mountain pastures, day in the mountain pastures, patron saint, religious processions, carnival, fireworks on Saint John's day, etc.); the recovery of old toys and games that were miraculously handed down to minority communities:  tsan, fiolet, rebatta and rouletta in Valle d'Aosta, cornichon and baculot, types of roulette, and fiolet in Faucigny and Chablais in High Savoie. The stories of evening get-togethers rediscovered in memories are collected, studied and presented by narrators: the Guivre and the dragon, werewolves and the devil, Gargantua and elf spirits, Sabbat and wild hunting, villages buried as divine punishment, fairies that were often evil and the wild man, a generous issuer of precious knowledge, good souls, the punished and the damned are no longer an expression of country ignorance but the artistic product of popular imagination.


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