Geological heritage

The island of grand spectacle
Viewpoint of Maïdo Saint-Paul - Reunion Island

Science, poetry, art and culture come together in numerous sites, small or great, common or unique in the world

For around three million years, volcanic and sedimentary phenomena have been striving to produce minerals, rock, water, shapes and landscapes, forging the image of the intense Reunion Island.
Science, poetry, art and culture come together in numerous sites, small or great, common or unique in the world : îlet Roche Plate, Ravine la Rouille, Cap Jaune, Cratère l'Eau Chaude, Source de la Roche qui Glisse...
However, often due to ignorance, numerous sites of geological value suffer degradations, whether or not reversible, altering the landscapes on "the island of grand spectacle".

Primary sites of patrimonial value

Three landscape units define the geological identity of the volcanic island and its heights :

  • The scene of active volcanism is situated at the shield volcano "Piton de la Fournaise", in the enclosure, a privileged place to explore the Hawaiian-type eruptions : lava fountains, spatter cones and ramparts, emissive crevices, aphrolithic lava flows, cored lapilli, scoria, Pele's hair, cow pie bombs, ribbon bombs, craters, lava tunnels...

  • The stratovolcano "Piton des Neiges" houses globally unique structures : the cirques, genuine geological endemisms of Reunion Island. A spectacular worldwide erosion (3000 to 6000 ft. of digging in only a few tens of thousands of years) allows to discover the history and architecture of an evolved intraplate volcano, whose "heart" (magma chambers) has even been exposed ! Hydrothermal vents on the other hand are recalling the volcano's recent activity !

  • A cheval entre les deux massifs volcaniques, la zone des pitons de la Plaine des Cafres n'est pas sans faire penser à un mini parc des volcans d'Auvergne, avec ses nombreux et esthétiques cônes volcaniques et ses tunnels de lave.

Other sites offering a strong patrimonial value that are worth mentioning:

  • the region of "la Plaine des Sables", rich in various cones, projections and flows,
  • the site of "Commerson" crater and its flow "cascading" at the top of the valley of "la Rivière des Remparts",
  • the lava tunnels of "Tremblet",
  • the flow of picrite basalt outside the enclose passed through the village of "Piton Sainte-Rose" in 1977,
  • the upwellings and waterfalls of "Grand Galet", "Cap Blanc" and "Caverne Rouge",
  • the major historical landslide of "Mahavel" (1965)
  • the volcanic lake dam and the lake of "Grand Etang",
  • the upwellings, waterfalls and basins linked to fossil topographies and flows of "Takamaka" valley and "la Rivière des Roches"; etc.

Secondary sites of patrimonial value

In the area of "la Fournaise", basically the regions surrounding the sector "Enclos-Plaine des Sables" are concerned, offering the chance to observe magnificent lines of volcanic cones accentuating rift zones (Puy Raymond), as well as paleotopographic figures molded by lava flows (Basse Vallée).

The area of "le Piton des Neiges" includes:

  • the paleocirque "Bébour-Bélouve", covered over several hundreds of feet by the fruits of the last great phase of activity of "le Piton des Neiges", enclosed by the formation of lava domes (Cap Anglais) and proclastic flows (Bélouve) around 25000 years ago.

  • the paleocirque "Les Makes", flooded by lava flows where as a result, molded figures, tunnels, caves, caverns and holes have been noticed.

  • the slabs of "la Roche Ecrite" and "Maïdo", with a rough, prismatic debit (large blocks) and consisting of welded projections,

  •  the old residual basaltic plateaus of "le Morne du Bras des Lianes", "la Chaine du Bois de Nèfles" and "Entre-deux",  the spectacular "corrugated" morphology and ferralitic soils.

  • the canyons, lava flows, waterfalls and basins of "Bras de la Plaine" and "Grand Bassin".

Bringing the island's rich natural heritage to the attention of the masses could be the best way to protect the environment of Reunion Island... provided that a management strategy is installed focusing mainly on the creation of numerous local jobs in the following fields:
 protection of the authenticity of the sites (eco-guards),
 discovery (guides,...), reception in the peripheral area (accommodation, restoration, etc). 
Let us hope that the label of national park may guarantee an authentic management of the environment and a sustainable development of the Reunion heights.

Article by Jean Louis HAURIE - geologist