Cape Verde Islands

Friday 25.07.2014

 

Volcanism

 

Cape Verde: Volcanoes in the Atlantic

The Cape Verde Islands were created by magma rising through the ocean, which is why they never were part of the African continent. (Certain animal species are not present on the islands as a result).

The eastern islands were the first to rise up out of the Atlantic and are therefore the oldest (Sal, Boavista and Maio). They are considered extinct.

 
Volcanoes on Cape Verde, Cape Verde Islands
Central crater with fumaroles

But there are also clear signs of past volcanism here. For example, numerous craters can still be identified on these islands and the crater floor of the salt pans near Pedra de Lume on Sal has a temperature that is very warm to hot. This can easily be felt when entering the basin. The “heating” of the salt pan floor can probably be attributed to the volcano’s residual heat. The (Pico de) Fogo on the island of the same name – whose last eruption in 1995 created the Pequeno Fogo – is the only active volcano at the moment. This was a flank eruption, which means that the main crater did not eject any lava; instead, it comes from the Pequeno Fogo (Little Fogo) that was formed as a parasitic volcano. You can see an impressive film about it at the municipal museum (Museu Municipal) in São Filipe on Fogo and discover visible volcanic manifestations in the main crater. Hot sulphur steam escapes from fumaroles (hot steam emissions) in light whitish-yellow hillside regions. This can also be smelled when the wind blows in the “right“ direction (has an odour like rotten eggs).

 

There are also hot spots at Pequeno Fogo with fumarole activity. It is advisable to just hike around here with shoes that have good soles. The ground is very hot in places!

In 2005, volcanologists of the Leibnitz Institute in Kiel discovered a volcano field to the south of the Santo Antão Island with some seamounts. These are undersea volcanoes that have not (yet) reached the water’s surface and will cause the creation of a new Cape Verde island in the future.
This volcano field was named the Charles Darwin Volcano Field in honour of Charles Darwin.

Pequeno Fogo with hot spots (hot spots are sulphur deposits, sometimes with fumaroles)
 

But seamounts are not just located in the most recently discovered volcano field. Some are also located in the surrounding area of the other islands, which make them an invisible component of the archipelago.

There is also a warm spot in the ocean on the north coast of the Santo Antão island that is not heated by a fumarole and does not have a thermal spring escaping from the ocean floor. More precise information on this is not available and still requires scientific research.

Almost all of the islands have interesting rock formations that were created by the volcanism. You can marvel at the most impressive rock deformations and layers on Santo Antão and Fogo.

No one can predict when the next eruption will occur and where (not only on Fogo).