Massif du Mercantour-Argentera
The Mercantour-Argentera massif is a massif in the Maritime Alps located astride the French departments of Alpes-Maritimes and Alpes-de-Haute-Provence and the Italian region of Piedmont. The name of the massif comes respectively from the summit of Mercantour, a secondary central summit, and from Mount Argentera, the highest point of the massif, entirely in Italy.
The massif is partially covered by two natural parks, the Mercantour national park on the French side and the Maritime Alps natural park on the Italian side. These parks are important because they protect many rare animal and plant species, like Speleomantes strinatii and Saxifraga florulenta, which is only found in this massif and used to be a symbol of the Mercantour Park. The massif is also full of rivers and lakes, most of which were formed during the last Ice Age and are found in the basins of the massif's crystalline rocks.
This area has been home to humans since the Early Bronze Age, with signs of this early occupation particularly visible at Vallée des Merveilles. Human presence in the area grew during Antiquity and the Middle Ages, notably with the establishment of the salt route. In the 20th and 21st centuries, the massif has become a popular destination for tourism and recreation. The area offers a range of outdoor activities and sports, including ski touring, alpine skiing, cross-country skiing, hiking, mountaineering, and canyoning. Today, the economy of the massif is primarily focused on the tourism sector, which has largely overtaken agricultural and industrial activities.
The massif is associated with an important cultural heritage, which inspires artists as evident in its representations and appearances in painting, cinema, music and literature.
Toponymy
In France, outside of academic circles, the massif is commonly referred to as the Mercantour massif. This name generally refers to the French part of the massif, which tends to be confused with the territory of the eponymous national park, although the latter is smaller in size.The name massif du Mercantour is commonly used in the 21st century. However, its origin is attributed to a mistake made by French military topographers in the 19th century. These topographers, while conducting triangulation measurements from Côte d'Azur, identified a peak that appeared to be the highest. Upon visiting the location, they were informed by local shepherds that the mountain was known as the summit of Mercantour. Contrary to their initial perception, this peak does not exceed an altitude of 3,000 meters. The reason for their misjudgment was that from the coast, Mount Argentera, which is actually taller, was obscured by the Mercantour peak in their line of sight.
The etymology of "Mercantour" is based on a legend. Following the Roman conquest of Gaul, the newly acquired territory required a distinctive name. Informed by the prevailing Latin language of the Roman Empire, the Romans coined the term "Marcamtor" for this region. This composite name drew from three key elements:
- Mar: Symbolizing the sea.
- Cam: Representing the path or route.
- Tor: Denoting the mountain.
In France, the Italian part of this territory is called the Argentera massif. However, in Italy, the entire massif is named Alpi Marittime.
Geography
Location
The massif extends over the border part of the mountain range between the Rocher des Trois-Évêques and the Col de Tende.Geomorphology
The massif is made up of a main range, oriented northwest–southeast, which serves as a natural Franco-Italian border. The crest line of this range represents a little more than 70 km. Four main orographic nodes exceeding 3,000 m altitude can be distinguished, from east to west:- the Gélas-Malédie-Clapier group, Gélas being the highest peak of the massif on the French side;
- the Argentera group, whose southern summit is the highest peak of the massif;
- the -Matto group ;
- the - group.
- in France, these are the valleys of Var, Tinée, Vésubie, and Roya ;
- in Italy, these are the valleys of, Stura di Demonte, and Vermenagna.
The relief of the massif covers the entire northern half of the department of Alpes-Maritimes, in France, and the eastern end of the province of Cuneo, in Italy.
Access
The western and central areas of the massif are accessible from various routes. From the south, one can reach it from Nice via the Boulevard du Mercantour. This route serves the D6202, M2205, and M2565 roads, leading to the Var, Tinée, and Vésubie valleys respectively.The eastern part of the massif can also be accessed from Nice via the D2204 road, and from Ventimiglia via the SS20 road. Both these roads converge at the Roya valley.
To the north of the massif, the Departmental Road 900 in France, which becomes the S21 and then the SS21 in Italy, connects the towns of Barcelonnette and Borgo San Dalmazzo. This route skirts the relief and serves all the valleys located to the north of the massif.
The Mercantour Massif is also accessible by rail. The train des Pignes, which connects Nice to Digne-les-Bains, runs along the southwest end of the massif. On the eastern side, the railway lines from Nice to Breil-sur-Roya and from Cuneo to Ventimiglia, often referred to as the Tende lines or the "Train of Wonders", provide access to the town of Tende.
Main summits
Hydrography
The French part of the massif corresponds largely to the watersheds of the tributaries on the left bank of the Var and the right bank of the Roya,. On the Italian part, the massif corresponds to the right bank watershed of the Stura di Demonte, up to Cuneo.Lakes
The massif is home to just over 200 lakes, making it one of the territories with the highest lake densities in the French Alpine massifs. The origin of these lakes is primarily glacial. They are situated in basins that were formed by the erosion of glaciers during the Würm glaciation.Major lakes in the French side :
Major lakes in the Italian side :
Watercourses
The massif benefits from more abundant rainfall than the surrounding low valleys and plains and plays the role of a water reserve for the latter. Notable watercourses within the massif are as follows:Glaciers
The massif was characterized by the presence of several glaciers by the end of the 20th century. During the early 1930s, these glaciers, located on the Italian slopes, covered an area of approximately 200 hectares. However, by the start of the 21st century, these glaciers had either vanished or were reduced to inert ice beneath the moraine. At the beginning of the 20th century, the main glaciers of the massif were the following:Geology
Orogeny
In geological terms, the massif has an elliptical shape with a northwest–southeast axis. It is part of the external crystalline massifs of the Alps chain, being the southernmost of them. This massif is a fragment of the continental crust of the Hercynian chain. It has undergone deformation and Alpine metamorphism, with the events of the Alpine orogeny superimposed on Paleozoic events. This has resulted in a massif composed of very old crystalline rocks, dating back at least 350 million years.Four main complexes can be distinguished within the massif:
- the Tinée complex ;
- the Gesso-Stura-Vésubie complex ;
- the Permian granites, in the center of massif;
- the mylonite of Valletta-Mollières, crossing the massif from one side to the other, along the northwest – southeast axis, composed mainly of mica schists.
Glaciations
The study of Alpine glaciations has shed light on the impact of glacial periods on the massif. While knowledge about very ancient glaciations remains fragmentary as of the early 21st century, the effects of the Riss and Würm glaciations have been better understood since the early 20th century. The Würm glaciation, in particular, significantly reshaped the landscapes and altered the moraine traces of the Riss glaciation. Field data analysis, especially from the Italian Stura di Demonte valley, has helped establish the glacial maximum during the Riss period. The maximum advance of the glacier terminus was located between the communes of Saint-Martin-Vésubie and Lantosque in Vésubie on the French side. During the Würmian period, the Gordolasque glacier, which was particularly large, reached a thickness of 300 meters.The traces left by these glaciers are visible within the massif in the form of erratic blocks as well as rocks scraped or polished by the action of ice are widespread there, particularly in the Merveilles and Fontanalbe valleys.
Seismicity
The French part of the massif is mainly located in a zone of average seismicity. The Vésubie valley in particular was affected by major earthquakes during the 15th, 16th and 17th centuries. The Italian part of the massif is located in a zone of low to medium seismicity.Climate
The climate of the massif is characterized by hot and dry summers and mild winters, typical of a mountainous region. The climatic conditions within the massif are diverse due to its geographical location, being subject to both Alpine influences in the north and Mediterranean influences in the south. Consequently, the massif experiences milder temperatures, on average for a given altitude, compared to massifs located further north.The existence of three topoclimates, namely,, and fond de vallée, is confirmed by records from meteorological stations installed in the upper Vésubie. Rainfall patterns across the massif vary, decreasing from east to west. The Roya valley receives the highest rainfall, while the Var valley receives the least. Overall, the massif experiences abundant precipitation, exceeding 1,000 mm per year, which is often intense, especially in autumn.
The massif is sensitive to the Foehn effect and is influenced by the depression of the Gulf of Genoa, which results in cold winds, such as the Lombarde wind, blowing from the east. In winter, the snow cover follows the same geographical distribution as precipitation and can often reach several meters. The massif is also experiencing the effects of global warming, with an increase in temperature of 0.3 °C per decade over the period from 1959 to 2009.