The remains of the Armorican Massif
Brittany rests on a two billion year old base, the Armorican Massif. Shaped by upheavals, folds, volcanism and sediment deposits, this mountain range, sometimes worthy of the Himalayas, sometimes engulfed under the seas, has been largely eroded over time.
The millennia have thus sculpted a very hilly relief, with gentle slopes, interspersed here and there with deep valleys. To the west, two lines of rocky ridges have resisted erosion: the Arrée Mountains to the north and the Black Mountains to the south. The former contain the highest points of the region, which are vying for the title within a few centimetres of each other: Roc'h Ruz, Roc'h Trévézel, Roc'h Trédudon and Ménez Kador are all around 385 metres high. Not far away, the Mont-Saint-Michel de Brasparts titillates these summits at 381 metres. While in the extension of the Black Mountains, at the entrance to the Crozon peninsula, the Ménez Hom offers one of the most spectacular panoramas of the region, from the top of its 330 metres.
The Armorican Massif is also characterized by its geological diversity: sandstone formed by successive deposits of sand, limestone falun from shell debris, clayey and crumbly kaolins, gneiss, slates, shales, micaschists? Without forgetting the emblematic and omnipresent granite, with its multiple colour variations: grey, blond, blue or the famous pink granite, which has given its name to one of the most beautiful stretches of coast.
Between Ploumanac'h and Trébeurden, the poetic chaos of the Pink Granite Coast was born some 300 million years ago, when magma, rising from the depths of the Earth, piled up in underground pockets in the depths of the Armorican Massif. It cooled very slowly, giving this coarse-grained granite, pinkish with feldspar crystals. Erosion eventually exposed these soft and rounded rocks, sculpted by water and wind. In Ploumanac'h, they have taken on particularly picturesque shapes, while the Renote Island, in Trégastel, concentrates blocks of colossal size. It should be noted that this young granite rubs shoulders with two billion year old gneiss, the oldest rocks in France, notably visible at the Bihit point in Trébeurden.
The Armor, a coastline with many faces
A peninsula surrounded by the English Channel and the Atlantic, wrapped in some 2730 km of coastline, Brittany has the largest seafront in France. This very indented coastline offers a wide variety of faces, sometimes wild and wildly beautiful, rocky landscapes from the end of the world exposed to the winds and raging waves, sometimes gentle with Mediterranean accents, with its sheltered coves and turquoise waters. Sceneries that are often close to each other.
Dunes, strikes, mudflats, large sandy beaches, intimate creeks, jagged coastlines, spectacular cliffs, dizzying peaks? The landscape changes, on average, every kilometre! You have to walk along the famous "Sentier des douaniers" (customs officers' path) to realize this tremendous diversity. Formerly used to prevent smuggling, the route criss-crosses almost the entire Brittany coast, except for a few jealously privatized portions. Rather little concreted, the Breton coast is also punctuated by ports and anchorages, old fishing villages and family seaside resorts, which have kept their Belle Epoque charm.
A changing coastline that the movement of the tides, particularly powerful in the north, is constantly reinventing: the seaside landscapes are never quite the same. The amplitude of the tides - the strongest in Europe - can reach 14 metres in the bay of Mont-Saint-Michel and the sea retreats for several kilometres in the bay of Saint-Brieuc. It then discovers vast foreshores, rocks and islets that are temporarily accessible..
Each stretch of coastline has forged its own character: the polders, salt meadows and vast expanses of sand of the Bay of Mont-Saint-Michel; the pretty seaside resorts and lush green shores of the Emerald Coast; the cliffs of schist and pink sandstone bristling with moorland around Cape Fréhel and, opposite, those of Plouha, the highest in the region, steep walls of gneiss and granite... The wild and jagged coasts of the Trégor resemble those of North Finistère, dotted with a multitude of reefs and islets, lighthouses, white sandy beaches and deep estuaries. The Finisterian point, exposed to the elements, offers grandiose landscapes, like the Pointe du Raz. The southern coast, from Cornwall to the mouth of the Vilaine, is more built-up and more peaceful, with its low coastline planted with pine trees, its chic resorts and its beautiful, well-sheltered sandy beaches... The Quiberon peninsula and its wild coastline provide a quietness that cuts into the peace and quiet. The ria d'Etel and the Golfe du Morbihan, small quiet inland seas dotted with islets, offer postcard views.
The Argoat mosaic
Inland Brittany is less populated than the coastal belt, characterised by a scattered habitat and predominant agriculture. Inland Brittany has four main types of landscape: the bocage, which constitutes the main part of the landscape, moors, forests and marshes.
The Argoat, literally "the edges of the woods", no longer has many of these: the Armorican Massif, once covered with trees, has suffered extensive deforestation since the agricultural boom of the Neolithic period. So much so that Brittany is today one of the least forested regions in France. The mythical Brocéliande exists only in legends, even if it is commonly associated with the forest of Paimpont, the largest in the region. Forests of more than 10 km² can be counted on the fingers of one hand, but there are many wooded areas.
The largest forest in Brittany is linear: it is formed by the bocage. Shaped by man, made of slopes, trees or hedges, sometimes with low walls, it protects crops from the vagaries of the climate (wind, sun and bad weather). It limits runoff and soil erosion. A refuge for biodiversity, it also serves as a corridor for wildlife. The bocage was greatly affected by the land consolidation of the 1960s, which caused hundreds of thousands of kilometres of it to disappear and created in certain areas vast fields pruned for intensive agricultural practices: this is the case, for example, around Loudéac and Pontivy, while the areas around Rostrenen and Fougères, the Monts d'Arrée and the Montagnes noires have preserved a dense bocage. Today, efforts are being made to reconstitute it.
Another emblematic landscape, the moorland is also becoming scarce, which has been undermined by agricultural modernization. Unlike coastal heathlands, which grow naturally, inland heathlands are the result of man-made clearing. In the past, these common areas were used as pastureland and provided the farmers with bedding, fertiliser and fuel. In those days, heathlands covered 30% of the land area, compared to just 2% today. The largest remaining moors are in the Arrée Mountains, which also contain peat bogs. They are also found, scattered among fields and woods, in the forest of Paimpont, the region of the Landes de Lavaux... We can also mention the moors of Locarn, Liscuis or Ménez Hom.
Finally, the region has swampy areas, mainly on the south-eastern borders, where the topography is low and flat: Muzillac, Séné, Redon country...
A dense hydrographic network
The region is criss-crossed by many small coastal rivers, especially in the west. Fed by thousands of streams, these short, fast-flowing rivers originate in the relief of inland Brittany and flow into the English Channel or the Atlantic Ocean. They often lead to wide estuaries, sometimes very deep, called abers in Breton, which sink deep into the hinterland and in which the tides rise far upstream. This is the case, for example, of the Blavet, the Rance, the Jaudy or the famous North Finistère estuaries (Wrac'h, Ildut and Benoît), which look like fjords.
To the east, the landscape is flatter and the Vilaine River flows slowly over some 230 km. It is the longest river in the region, ahead of the Oust, the Blavet, and the Aulne. The Nantes-Brest Canal, built in the 19th century, links several rivers to cross the whole of central Brittany, while the Ille-et-Rance Canal connects the English Channel and the Atlantic, via the Vilaine. Several dams form artificial lakes: the largest is that of Guerlédan, on the Blavet. We can also mention the lake of Jugon, on the Arguenon, or the lake of Brennilis, on the peat bogs of Yeun-Elez in the mounts of Arrée.
Alas, Breton rivers suffer from several problems and only a third were considered to be in good ecological condition in 2019. They mainly suffer from nitrate and pesticide discharges due to intensive agriculture, which are the source of green tides affecting parts of the coastline.
The weather forecast: a rain of comments
It's a never-ending subject of jokes, sayings and more or less benevolent comments. If the Breton weather is so much talked about, it is probably because it is constantly changing, imposing its mark on the landscape and daily life.
It is rare for the sky to remain invariably blue or desperately grey. It is more like a ballet of clouds and can alternate, in the space of a few hours, between rainy episodes and triumphant clearings. "In Brittany, the weather is fine several times a day" and one can experience "the four seasons in one day", as we like to say here.
Cradled by the Gulf stream, Brittany enjoys a mild oceanic climate, characterized by summers that are not too hot and winters that are not too cold, warmed by westerly winds. As for rainfall, except in Finistère, it is rather within the national average, far from the rainy reputation that sticks to the Breton skin.
There are nuances depending on the area: the coast is generally milder, when the interior is cooler and more humid. The Gulf of Morbihan enjoys very good sunshine, as does the Rennes basin, which is not very rainy. Whereas to the west, the reliefs form a barrier to clouds and record heavy rainfall.
Extreme meteorological phenomena spare the region. Nevertheless, storms regularly pass through the region. The region is little affected by heat waves and is not immune to climate change. The main risks are linked to erosion, marine submersion and water resource management.
