On the 20 sea miles from Punto de Papagaio to Puerto del Rosario the sandscapes kept amazing us. Just like Lanzarote, Fuerteventura makes a barren impression. Its surface shaped by volcanoes and erosion. This time not smooth and velveteen like but corroded, like a giant stone muncher had passed, biting off big chunks, and spitting sand and pulverized stones all around. We wondered how this all came to be and found the following answer…


The Canary hotspot

The volcanic archipelago was created by the Canary hotspot. Mind that this bears no relation to free internet connection, but rather refers to the geological birthmother of the islands.

A hotspot is a place with high volcanic activity. In some cases the underlying earth mantle is way hotter in comparison to the surrounding mantle, hence its name. Whereas it was once believed the hotspot originated from the slow movement of a tectonic plate across a hot region beneath the surface, it is now widely accepted to be caused by a mantle plume. This is some sort of narrow chimney arising from way down deep in the Earth’s core–mantle boundary, allowing mantle magma to surface. In other cases, the hotspot does not seem anomalously hot and would be caused by passive rising of melt from shallow depths.

The Canary hotspot started forming on the ocean bottom, close to a passive continental margin of the African tectonic plate, when dinosaurs were still roaming the earth. The (s)pot started brewing underneath Fuerteventura 70 million years ago and reached boiling point about 40 million years ago giving rise to the submarine volcanoes from which Fuerteventura engendered. Over millions of years there has been a slow progression of the volcanic activity, presumably because the African plate is slowly creeping westward.

Volcanic islands also have a type of life cycle. They start off under water (submarine stage) with their volcanoes on full blast, pushing magma and lava out, growing steadily until they peek out their head above water (the emergent stage). This forms the core of the island, containing submarine sediments and volcanic rocks. In the shield-building phase, basalt and lava flows solidify around the core. The volcanoes start taking a rest in the declining phase and the surface stones are exposed to the unabatingly eroding powers of weather, wind and sun. Coral reefs are deposited under water while the elements continue to landscape the islands aerial surface (erosional phase). Fresh volcanoes ignite and give the island a face lift during the rejuvenation phase.

Formation stages volcanic islands – hotspot (Walker, 1990)                

Should you have any doubt that rejuvenation is spectacular, consult the testimony of the priest on Lanzarote: ‘From 1730 to 1736, the island was hit by a series of volcanic eruptions, producing 32 new volcanoes in a stretch of 18 kilometers. Lava covered a quarter of the island’s surface, including the most fertile soil and 11 villages. 100 smaller volcanoes were located in the area called Montañas del Fuego (Mountains of Fire)’. The volcanoes cooled down, to erupt again 90 years later. With a lot of the fertile land gone, the settlers were in a bit of a pickle. When winter rains failed the subsequent drought sparked a mass emigration to Cuba and the Americas.

The Canary hotspot is definitely still hot. The chain has been active along its entire length during the last million years. Four islands are currently in the rejuvenation stage – Fuerteventura, Lanzarote, Gran Canaria and Tenerife. They have historical records of eruptions since European discovery. La Gomera is in the erosional stage. It has not been active in the last million years. La Palma and El Hierro are in the declining stage. And it is not impossible that new islands will be added to this archipelago. In the summer of 2011, several thousands of small tremors were recorded on El Hierro, resulting from magma movement beneath the island. A subsequent big fissure and volcanic activity on the ocean floor was recorded. Time will tell if El Hierro will be enlarged or a new island will be created…

Apart from volcanic peaks sticking out, the islands in the Canary chain often have steep ocean cliffs caused by landslides and catastrophic avalanches of debris.

Three Canaries

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