Granite quarries

What is granite?

Granite is an assemblage of quartz crystals, feldspar and mica flakes. This assemblage of grains, from the Latin "granum" gave the name of granite. Note the two spellings of the word for two different contexts: -granit for quarrymen and architects -granite for geologists

The origins of granite

Granite is an eruptive rock rising from the magmatic depths of the earth. Cracks occurring in the earth’s crust, under strong pressure of magma, the latter reaches the surface of the globe giving volcanoes. However, it is only when the magma stops its rise towards the surface that it constitutes the granite, kind of volcano "aborted". Granite was formed in Trégor 300 million years ago when a huge pocket of magma was formed underground at 4 or 5 km deep, from Trébeurden to Ploumanac’h. A few hundred thousand years later, the magma was completely cooled. This long cooling has favored the formation of mineral crystals. The longer the cooling, the larger these grains of minerals. This is our granite that was made visible thanks to the gradual erosion of the soil, thus discovering the rocks hidden in the depth of the earth.

Tetror granite massifs

There are three different granite beds:
- massif linking Perros-Guirec and Bréhat (the oldest)
- Plouaret massif
- massif of Ploumanac’h in Trébeurden 3 kinds of granite: granite of Clarity (large pink to red feldspars) blue and white granite of Ile-Grande
A little history

- 6000 to 6500 years ago, rise of the first megaliths Ex: dolmens island Bono and Trébeurden, menhir of Pleumeur-Bodou and covered walkways of Trégastel and Ile-Grande

- A few millennia later, Gallic stelae of Trébeurden or Plestin-les Grèves

- From the 12th to the 17th century, construction of chapels and churches Ex: Tréguier cathedral built with granite from Ile-Grande Construction of granite houses until the 20th century

- 19th century: industry and trade develop Construction of houses, factories, docks, lighthouses, bridges, viaducts, paving stones, ...
Exploitation of granite on Ile Grande

The success of the granite of Ile-Grande stems, first of all, from its undeniable practical aspect: because of its insular situation, the granite reserves are easy to reach and immediately available. In addition, since most islets of Ile-Grande are uninhabited, the sites do not represent any extraction constraints. Finally, note the great quality and diversity of Granite Island-Grandais. From a regional point of view, it was here that extractions were most active from the second half of the 19th century to the beginning of the 20th century and these 14 hectares of quarries constitute the finest example of granite quarrying. by the seaside...

From the end of the Middle Ages and during the Renaissance, the extraction of granite from Ile-Grande is necessary for the construction of churches but it remains marginal. It is only from 1827 that the Municipal Council, anxious to preserve the viability of the roads and to control the "wild" extraction, while benefiting from this trade, decides to legislate on the exploitation of the granite. From 1950 onwards, reefs and small islands of the archipelago are leased to operators for successive periods of 6 to 9 years. Carriers come from everywhere, especially the Chausey and Cotentin Islands. Between the years 1860 and 1910, the population doubled. Fifty years during which the extraction of granite, of the order of 800 tons per day, will be at its peak on Ile-Grande which becomes "the island of the carriers". Cobblestones, curbs, quay walls and more, the granites of Ile-Grande are exported to the coasts of the Channel and the Atlantic. Landed in ports such as Caen, Cherbourg, Boulogne, Dunkirk, Bordeaux or Bayonne, partly used on site, they are routed to many inland areas such as Le Havre, Rouen, Paris, Pau, Lourdes, etc ... Brittany itself, they will be used for the construction of the Lighthouse des Héaux at Bréhat, the viaduct of Morlaix, the lighthouse of Triagoz, the church of Louannec, the station and the aqueduct of Saint-Brieuc, the quai de Portrieux , the Lézardrieux viaduct and more!

Some great careers

- Kastell Erek This quarry is the most important of the projects, both in terms of extension and volume of extractions. A thick wall, still visible today, will be built to protect it from the entrances of the sea. The blue and gray granites will be extracted from 1908 to 1979, date of the end of exploitation since the quarry will be ceded to the Protective League of Birds.

- Toul ar Staon The tip of Toul ar Staon is a rocky tongue on the west of the Ile-Grande where the erection was intense from the beginning of the century to the end of the 1940’s. There are still visible the ruins of former gingerbread houses, transformed into a hostel bombed by the Germans during the Second World War.

- Carrière Roïc Facing the covered walkway, this quarry was endowed not only with an extraction site but also with a storage area and a pruning workshop.

- Quarry Brintec’h An extraction site that overflows with water when the sea is high, the Brintec’h quarry, named after its operator, was exploited from 1930 to 1960 for its blue granite.

- Ile Corbeau (Enez Vran) The island still has traces of intense exploitation of blue granite with black or gray mica, which is why a forge was built on the flat part of the site. Only the Île-Grandais were entitled to extraction, the only drawback being the transport of granite to a loading dock.

- The West Islands Agathon: one of the largest quarries on the islands, with a railroad for loading stones. There remain the ruins of the forge and shelters. Ile Losquet: it was the object of an intensive extraction and shelters today the equipments of France Telecom. Ile Fougère: chosen to supply the viaduct of Morlaix among others, there are still the remains of a wharf and buildings.

- The islands of the East Morvil Island: characterized by the extraction of blue granite, this island was used for the construction of the lighthouse of Héaux de Bréhat. Plate Island and Aval Island: also famous for their blue granite. Ile Jaouen: also supplied the viaduct of Morlaix.

The transport of granite

Bricks, schooners or barges have long been the only means of transporting the granite blocks that were then loaded at low tide. When these boats could not dock, we used the "cuckoo", a kind of small barque-well that could raise 7000 kg blocks taken at high tide under the hull and thus carried the granite to the largest ships. But navigation in the middle of the pitfalls is dangerous and many boats such as "Providence" or "Mathilde" will beach near the coast. It was not until 1907 that a rail embankment was built by the quarrymen themselves at the current Saint-Sauveur harbor. Routed by small train from the various quarries of Ile-Grande, the granite blocks were then embarked on gabare or other boat, transported to the quai du Leguer and then wheeled to Lannion station.

Life of the Carriers

The exploitation of granite is one thing, the daily quarry is another. And finally, more than the industrial or artisanal aspect, it is the human resources that determine the true identity of a place or a commune. The living and working conditions of these men were very difficult. At Ile-Grande, the sons were either sailors or carriers, depending on their father’s choice. And for these sons, it was better to embark on a ship than to be a stonemason, a job that was harder and less popular. At the age of 12-13, they left either as a moss or apprentice-carrier. No matter the weather and the outside temperature, you had to go to work. It was only in the case of extreme weather conditions that the quarrymen working on the islets turned around, rain, wind, mist that prevented them from reaching their place of work. When it was really cold, the quarrymen would warm up around the hearth of the forge and drink a bowl of hot soup. It was the women who brought them the lunch when the amplitude of the tide allowed them: potatoes, bread soup, bacon, periwinkles, barnacles, and for drink brandy and "piquette", drink based slices of boiled apples. The quarrymen were most often paid for the task, and this for a fee often derisory, 4 to 7 francs (maximum exceptional, applied on the island Fern only) per day. Not only poorly paid, the workers had to endure a large daily hour range of about 12 hours, especially the summer by the length of the days. Finally, the risks of the trade were not negligible, tailor, splitter, polisher or blacksmith, no one was safe from an accident.

In view of these harsh working conditions, Ile-Grande has every reason to be proud of the courage and merit of its quarrymen and have left traces of a memory that is still alive on every block of granite. peninsula.

The end of careers

From 1914, the shortage of manpower is felt at the dawn of this first world war which mobilizes many men. The war over, the quarrymen remain in short supply, the granite demand decreases along with the wages. A few handfuls of workers leave the farms of Ile-Grande around 1930 to win other careers, including that of Clarity, where they will be better paid. On August 16, 1936 (victory of the Popular Front), the workers lead a five-week strike following which they will obtain a salary increase of only 10 centimes. There will be conflicts of interest, mostly political, but also the bitumen era that will see the final decline of careers on Ile-Grande whose extraction will cease completely in 1989.

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