In the Auvergne-Rhône-Alpes region, the departments Ardèche and Haute-Loire share a common history, geography, and landscape. Both, divided by the Mézenc massif, lie in the southeast of the Massif Central. This Mézenc massif is a vast volcanic plateau formed by two “sucs” (volcanic domes): Mont Mézenc and Mont Gerbier de Jonc. Everything is doubled here: two departments, two peaks, and two highest points! Grab your hiking boots and pack your backpack, because we’re taking you to discover these strange dormant volcanic domes, called “sucs,” which are unique in Europe! And get ready for experiences that go beyond the beauty of the landscapes—we’re taking you to the boundaries of reality!
Map of departments showing the location of Mont Mézenc and Mont Gerbier de Jonc
Mont Mézenc, an astonishing suc!
Is Mont Mézenc an unusual feature in the landscape? Mont Mézenc is a pure « suc » characteristic of the Velay and Haut Vivarais regions in the Massif Central. It is not just a mountain, it is a Peléan volcano!
Panoramic view of Mount Mézenc, a mountainous fortress!
Mont Mézenc is known for being made up of two domes, half a kilometer apart and located in two different departments. The southern dome is the highest point in the Ardèche department, rising to 5,751 feet. The northern dome in Haute-Loire rises to 5,722 feet (1,744 meters). This ancient cumulo-dome rises above the Boutières abyss. The cliff of the Cirque des Boutières is all that remains of the crater of an ancient volcano, which was later eroded by glacial erosion. Often compared to a haughty giant, Mont Mézenc stands like a massive fortress crowning the ridge between the former provinces of Vivarais and Velay.
The Sucs: surprising geological formations!
Mont Mézenc, Information facts:
| Section | Detail |
|---|---|
| Municipality | Borée |
| Département | Ardèche and Haute-Loire |
| Area | Auvergne-Rhône-Alpes |
| Natural area | Mézenc Massif |
| Surface area | about 1,57 mi2 |
| Altitude | 5,752 feet |
The Sucs, these strange volcanic domes
The landscapes of Velay and Vivarais are marked by a succession of surprising geological formations « sucs ». These craterless volcanoes seem to burst out of the ground, like molehills, in the middle of wide open spaces! The word « Suc » is a very old term for a slightly rounded, protruding feature. Here, the monotony of the landscape as well as the illusion of its vastness are the essence of its beauty. On site, there is a feeling of infinity. But behind this uniform facade lies exceptional natural wealth.
The panorama from the Croix de Boutières offers a breathtaking view of the countryside from its summit. You can see the Boutières, the Suc de Sara, Mont Mézenc, and Gouleyou (or Goulëiou): three volcanoes, three shapes, and three stories!
- The Suc de Sara: a dome formed by low-viscosity lava. Its unusual shape attracted the inhabitants’ attention as early as the 14thcentury, when it was known as “Mont Aigu” (Sharp Mountain). It is largely the root of a volcano of which only the summit seems to have emerged… then the valleys were carved out, revealing the deep root.
- Mont Mézenc: a dome-shaped volcano. This colossal mountain rises majestically above the Boutières region. It was formed by several flows of viscous lava.
- The Gouleyou: a protusion dome. This is a typical example of a lava piston. Imagine a mass of very viscous lava rising very slowly over several years, pushed towards the surface simply by its low density.
Panoramic view from the Boutière cross: 3 volcanic peaks
You are also greeted by the view of a spectacular panorama! What could be more mythical than the story of a golden horse, worthy of legends and fairy tales, to begin our journey?
The phonolitic volcanism of Mount Mézenc
Once upon a time… there were volcanoes as Maestro says. Peléan volcanoes (i.e., those without craters) appeared nearly 12 million years ago. The formation of the Alps raised the old granite bedrock. Depending on the area’s topography and the viscosity of the lava, the volcanic development took on various forms: lava spires, domes, or simple lava flows.
« Mont Mézenc, guardian of the legends of Velay, stands majestically, a silent witness to the volcanic history of our land. »
Mont Mézenc is a complex phonolitic dome formed by the coalescence of several lava flows. This dome was gradually formed from several streams of viscous lava flow. Its name comes from the Celtic words “mez” (meaning space) and “enc” (meaning fire). Like all the other phonolitic reliefs in this area, it was formed at the end of the development of the eastern Velay volcanic massif, which took place around Mézenc between 7 and 11 million years ago. According to geological dating, Mont Mézenc is between 7.6 and 8 million years old.
ont Mézenc is an iconic volcanic massif with two distinct domes
Mont Mézenc is composed of two joined phonolitic domes that today form its two peaks: the first, “la croix du Mézenc,” on the northern side, and the second on the southern side. During the glacial periods of the Quaternary era, these phonolitic domes created cryoclastic blocks. Cryoclasty is fracturing caused by freezing! These blocks, wrapped in ice, were able to flow down the slopes of the domes like glaciers to form what are now known as “stone rivers,” also locally called clapiers or clapas.
« Sometimes rivers of stone flow between the folds, born of ice and fire »
The largest of these « stone rivers » dis Prapalos, on the southeast side of the dome. These rivers are now adorned with ancient ferns, mosses, and lichens. Half-plant, half-mineral they have existed for centuries on the slopes of the dormant peaks.
The Burle Triangle, the « Bermuda Triangle » of the Auvergne-Rhône-Alpes region
The Massif du Mézenc is a land of plateaus, punctuated by peaks exceeding 5,000 feet (1,500 meters) in height: Mont Alambre (5,548 feet), Mont Chaulet (5,318 feet), and Rocher Tourte (5,036 feet). The area is characterized by a harsh climate: it is swept by the Burle, a north wind that blows in winter, often accompanied by freezing temperatures. The Burle rages across the snow-covered plains, piling up the snow into drifts and shaping the tough character of its inhabitants. Its name is also associated with the “Burle Triangle.” This is a place where, like the Bermuda Triangle, a large number of air disasters have occurred. The Burle Triangle is a tantalizing mystery for aviation enthusiasts.
« An untamed wind that can create snowdrifts over eight meters high in just a few hours […], an uncontrollable wind that has caused more than one aircraft to be lost in the Cévennes and transformed this magnificent region into an open-air graveyard, filled with planes that have crashed into the ancient mountains of the Ardèche and Haute-Loire » (En quête du triangle de la Burle – Renaud Benoist)
The first plane crash in the area occurred in the 1930s, but it was during World War II that the legend of the Triangle de la Burle began. Several planes experienced problems while flying over the area, and accidents became more frequent. Since the 1940s, nearly 80 accidents—many of them fatal—have occurred in this small corner of France! Among the most notorious crashes was the one on 13 May 1948, when JFK’s younger sister, Kathleen Kennedy-Cavendish, died at a site known as « Serre du Péronnier ». Another notable crash occurred on 21 January 1971, when a twin-engine Nord 262 aircraft belonging to the French Air Force crashed at « Suc de Paradou » at an altitude of 4,403 feet killing leading figures in the French nuclear program, including the director of the French Atomic Energy Commission. This accident caused quite a commotion because rescuers found 22 bodies, even though officially there were only 21 passengers on board. Thus began the mystery of the
Mount Mézenc at dusk, swept by the burle wind
What caused all these accidents? Weather conditions are often blamed: icy winds blowing in gusts and freezing aircraft sensors may explain some of the tragedies, as may the terrain in this eastern part of the Massif Central. But can unpredictable weather alone explain all the crashes? Human error, suspected espionage, luminous spheres, and local legends add layers to these mysteries. The enigma deepens with planes that were never found—such as the « crash de rien » (Crash of nothing) on 18 December 1980. The aircraft disappeared behind a mountain. A large column of black smoke rose into the air. Yet searchers found nothing: not a single piece of debris, not a single clue. There are many theories about the « Burle Triangle » such as magnetic disturbances caused by electromagnetic clouds forming at high altitude with the Burle, or magnetic disturbances linked to the nature of the soil of the extinct volcanoes where France’s first uranium mines were excavated…
Mount Mézenc-les Estables, glowing sunset
The legend of the Golden Table is my favorite theory. At an altitude of over 4,600 feet, on the high plateaus of Mézenc, swept by the Burle wind, a centuries-old legend tells that the gold of the Kings of Velay (a huge golden table) is hidden under one of the three Teeth of the Devil. A maze of underground tunnels is said to lead to a Druidic crypt containing this mysterious treasure! This mythical object with supernatural powers is said to have been brought to Le Puy-en-Velay, after the sack of Delphi in Greece by the Vellaves (in Latin, Vellavi or Vellavii), a Gallic people whose territory was located southeast of the Massif Central. Entrusted to the druids of Mézenc, this stolen treasure brought only misfortune and the appearance of strange phenomena (magical or rather magnetic). Even today, this famous Golden Table is said to be the cause of the disorientation of aircraft instrument panels! Moreover, magnificent and strange golden sunsets can be seen from the village of Les Estables. The clouds reveal a golden sky then a glowing red sunset, before closing in on a dark night. Enough to keep the myth alive! Doubt and mystery still hang over these places.
« Twilight, how sweet and tender you are! The pink glows that linger on the horizon like the agony of the day under the victorious oppression of night, the lights of the street lamps casting opaque red patches on the last glories of the setting sun, the heavy draperies drawn from the depths of the East by an invisible hand, all imitate the complicated feelings that struggle in the heart of man at the solemn hours of life. » (Le Spleen de Paris, « Le Crépuscule du soir » – Charles Baudelaire)
Fin Gras du Mézenc: A culinary delight from the region
It is also in the Mézenc massif that lovers of finely marbled meat can enjoy the famous « Fin Gras du Mézenc », whose quality is protected at the European level by an Appellation d’Origine Protégée (AOP) label. But what is the secret behind the marbling of this beef? Rumor has it that Fin Gras owes its unique flavor to the hay found in the Mézenc meadows, including aromatic perennial plants such as Meum, which perfume the meat. So we set off in search of the secrets of « Fin Gras du Mézenc » with a visit to the Aubrac cows grazing at an altitude of 4,593 feet, near the small village of Les Estables.
Typical pastoral landscape of the Mont Mézenc region with its cows
The Massif du Mézenc is a land of plateaus renowned for its rich grasslands. Picture green hills, scattered forests, and peaceful cattle grazing undisturbed in the field. Add to this a crystal-clear blue sky and a refreshing breeze… These charming cows with their fawn-colored coats and fawn-colored eyes gather together, ringing their bells. They are absolutely gorgeous. Our presence triggered a commotion, as evidenced by the chorus of mooing. Surrounded by these naturally curious animals, we tried to take a few photos. There’s no doubt about it, just like Etienne Chatiliez’s 1995 film suggests « Happiness is in the field » ! Marguerite (Daisy in English), a classic cow name in France, is famously used in the film « The Cow and I » (La Vache et le Prisonnier). Marguerite and her cousins make a huge impression on us. But we’re still missing another part of the equation to uncover the famous secret of the « Fin Gras du Mézenc » ?
Mount Mézenc, cows with fawn-colored coats and doe eyes
The flora of Mézenc provides an exceptional habitat for these cows. From late spring onwards, the forests and pastures are covered with an abundance of flowers, creating a stunning palette of colors at these altitudes: pansies, gentians (Gentiana lutea), monkshood (Aconitum), lady’s mantle (Alchemilla), butterworts (Pinguicula), carnations, Aubrac tea (Clinopodium grandiflorum), bellflowers, orchids, and more. A profusion of colorful plants, more than 320 species compose the natural meadows of Mézenc. The list is too long to mention them all, but we find Siberian hogweed (Heracleum sibiricum), a large perennial plant in the family Apiaceae also known as « carrot flower », as well as wormwood, sweet chervil (Myrrhis odorata) with its aniseed scent, knotweed-leaved paronychia, yarrow (Achillea millefolium) with its medicinal properties, and black centaury (Centaurea nigra) with its purple tufts. We taste good-king-Henri (Blitum bonus-henricus), or wild spinach, and also meum (Meum athamanticum), or Alpine fennel. On the palate, it is an explosion of anise and licorice flavors. This very aromatic plant is only mowed on the slopes of Mont Mézenc. In the Alps, due to the very high altitude at which it grows, this plant is not harvested. Mézenc is one of the few places where mowing is done up to 4,900 feet, allowing animals to eat the plant.
Mount Mézenc, carnation flower
An immense variety of flowers and plants—including the famous Alpine fennel with its aniseed scent—grow together in the grasslands on the slopes of the Mézenc. Animals graze these meadows during the summer, and in winter, they feed on the harvested hay. These grasses, dried using traditional methods, nourish the calves and oxen, imparting a delicate, floral flavor to their meat. This is what gives Fin Gras du Mézenc its distinctive character!
Mont Gerbier de Jonc: The birthplace of the Loire River
Mont Gerbier de Jonc, the most famous volcano in the Ardèche region, is located in the commune of Saint-Martial on the border with Sainte-Eulalie. It rises to an altitude of 5,089 feet. Formed by a long-cooled lava spire it stands like a cone on the Ardèche plateau.
« Here, where the Loire has its source, every drop of water tells the story of the beginning of a thousand-kilometer journey »
Mount Gerbier de Jonc owes its popularity to what it represents: at its base lie three springs where the Loire, France’s longest river, begins its journey to the Atlantic Ocean. The “true” source is marked by a stone inscribed with the words: « Here begins my road to the ocean ». Classified as a protected site since 1933, it lies at the heart of the UNESCO Global Geopark of the Monts d’Ardèche.
Mont Gerbier de Jonc, Identification facts:
| Section | Detail |
|---|---|
| Municipality | Saint-Martial |
| Département | Ardèche |
| Area | Auvergne-Rhône-Alpes |
| Natural area | Mézenc Massif |
| Surface area | 1,08 mi2 |
| Altitude | 5,089 feet |
A journey to the summit: Climbing Mont Gerbier de Jonc
Mont Gerbier de Jonc is a phonolitic dome. The lava’s density gave it a compact shape. Around 7 to 8 million years ago the viscous, low-gas magma rose slowly and gradually through the faults and fractures in the bedrock to form this dome. The lava ascended through the chimney to the exit point without flowing away. As it cooled, it formed a phonolite lava dome in the volcano’s crater. As with Mont Mézenc, the Quaternary periglacial glaciations eroded the upper part of the structure, forming phonolite rubble at the base of the dome.
Mount Gerbier de Jonc is a phonolitic needle
At 5,089 feet high, Mont Gerbier de Jonc overlooks vast expanses of moorland and meadows. A 30-minute marked hiking trail leads to the summit, where visitors enjoy an exceptional 360° view of the Ardèche Mountains, the Cévennes, and even the Alps. The panorama to the west overlooks five other peaks in the Monts d’Ardèche Regional Park: Montfol (5,230 feet), Le Sépoux (5,020 feet), Le Séponet (5,033 feet), Le Taupernas (5,256 feet), and La Lauzière (5,190 feet), which has a flatter summit. From this pile of rocks, you feel as if you’re touching the sky—a strange sensation when contemplating these smooth-topped mountains. The mountains here are all approximately the same height. None of the peaks hides the others; you can see each neighboring peak and all the others. Absolutely nothing obstructs the horizon. It is a landscape of rounded mountains stretching as far as the eye can see, as if infinity were served on a platter.
Mount Gerbier de Jonc, spectacular view from the top
The Loire: a journey to the heart of its source at Mont Gerbier de Jonc
« The Loire River is the longest river in France. It has its source at Mont Gerbier de Jonc. ».
The river flows through historic cities—Orléans, Tours, Angers—and major wine regions such as Sancerre. How many generations of schoolchildren have memorized these sentences from their geography lessons? This unique peak is located on the watershed between the Mediterranean Sea and the Atlantic Ocean: on one side, to the southeast, lies a volcanic plateau, while on the other, to the northwest, stretches a rugged area of deep valleys and steep slopes. Mont Gerbier de Jonc is like a watering can: water flows out from all sides. Water penetrates easily because Mount Gerbier is made up of highly fractured volcanic rock. The water flows vertically until it meets impermeable rock. There, its flow becomes horizontal, and numerous springs appear. Some flow discreetly, such as the Eyrieux, a tributary of the Rhône, on its northern slope.
Just a few hundred meters further south, and the Loire would have headed to the Mediterranean! In fact, the Loire makes a false start. In its first few kilometers, it flows south towards the Mediterranean before encountering its first obstacle: the Suc de Bauzon, 4,803 feet high. Too big and too difficult to get through, it forces the Loire to change course after just 12 kilometers! This 90° turn gave its name to the village of Rieutord, which means « the river that turns ».
Mont Gerbier de Jonc is famous as the birthplace of the Loire River and attracts thousands of visitors each year. When you arrive at the foot of the famous peak, recognizable from afar, you will be surprised to see that the signs indicate not the source of the Loire, but the sources of the Loire: there are three points where the river emerges, from the « authentic » to the « true » source of the Loire, via the « geographical source ». All these sources can legitimately claim the title « the source of the Loire ». It is their confluence, a few kilometers downstream, that gives birth to the longest river in France: from the foot of Mont Gerbier de Jonc to the estuary at Nantes, it travels about 625 miles. A one-hour walk (about 2 miles) will take you on a tour of the sources:
- The « authentic source » is marked by a small monument erected in 1938 by the Touring Club de France. Since 2020, a new monument made of phonolite has been erected along the road.
- The « geographical source » flows into a stable trough. It is undoubtedly the most folkloric of the three… a tiny trickle of water is declared to be the “first stream of the river.” The spring water always emerges at 4° C.
- The « true source » is marked by a sign that reads « Here begins my journey to the ocean ». As proudly proclaimed on the sign indicating the trail, this source is registered in the land registry. This is from where the length of the Loire River is measured, giving this location a more « official » character.
Mount Gerbier de Jonc, true source of the Loire River
Once you have determined your preferred source from a reliable reference, you can continue the little game by guessing whether a small stream flowing peacefully through a meadow is already the Loire River or just an anonymous watercourse. Will this tiny stream, winding its way between rocks, ferns, and roots, gradually widen over its 625 miles journey to the sea and become the majestic river we know today? I threw a small stick into this stream so that it could make the long journey to the estuary–or not?
According to our sources (what a bad joke!), it’s time to head off to discover other great French natural spaces. Farewell to calves, cows, sheep, and so on, as Jean de la Fontaine wrote (more or less), and let’s continue to roam with a light heart like Perrette toward other adventures just a few steps from home!
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