The Canary Islands origin is related to lava
When you think about Tenerife, you think about El Teide. This rocky monument which rises in the center of the island is a symbol of this one, and of the whole archipelago. When you think about Tenerife, and also when you think about the Canary Islands, you think about El Teide. This geographic masterpiece is not only a mountain, but also a volcano. In other words, it is a sort of a giant chimney through which the lava can reach the surface of the Eart.
But El Teide is not the only volcano you can find in these islands. On the contrary, the Canary Islands origin is volcanic. In fact, these portions of surface which stay over the sea are not fragments of a continent. These islands have been formed through successive and extended emissions of lava. But, after all, where does the lava comes from?
The submarine volcanos are responsible
for the Canary Islands origin
The most common volcanos for us are the ones which appear on the Surface, but they are not the only ones. There are volcanos in the bottom of the sea, too. They are identical to the others, but they happened to appear under the water. They eject magma, too, which becomes lava when it contacts the exterior –in this case, the water-.
These cited volcanos, thousands of years ago, started to eject lava, and it provoked the Canary Islands origin. This is possible, for there is a series of fractures in the earth crust. They are known as structural axes and allow the exit of the lava. We must add that this happened in a hot spot, not in the border of two tectonic plates.
Successive volcanic series were necessary
to generate the Canary Islands
Successive emissions –called volcanic cycles- during an enormous period of time, provoked that the amount of lava reached the surface. In other words, this provoked the Canary Islands origin. Although they all have the same origin, every island has its special landform, completely different from the one present in every other island of this archipelago. This is due to both differences in their evolution and in the lava composition.
These emissions began around 40 thousand years ago with the Submarine Series, which formed the so called Basal Complex. It is the basis of every island, and it is formed of sedimentary residues, pillow lavas and a network of volcanic docks. But we have to bear in mind that, although the emissions of lava were very big, there are a long distance to cover, for the bottom of the sea in this area has a depth of 3000 meters.
So, something else must have happened. The key to emerge these lava emissions, which will become islands, was the ballooning and subsequent lifting of the insular block. After this event, it is believed the oriental islands –Fuerteventura, Lanzarote- might have reached the surface. This must have happened 20 thousand years ago.
There came the moment when the Canary
Islands reached the surface
The subsequent series were the first ones in which the lava contacted the atmosphere, and not the water. These ones are called the Miocene Series. It is believed that it began in the oriental and central islands, around 15 to 20 thousand years ago. The occidental ones, such as La Palma, this process might have started a lot later, around 2 thousand years ago. The type of lava in these emissions was the basaltic one, which is very fluid.
After this, there was a period of inactivity which lasted around 2 thousand years. And then, the third series appeared. They are called Pio-Pleistocene Series. As it is expected, these series ejected the lava directly to the atmosphere. The type of lava was the basaltic one, too, but combined with other ones, of different nature. Among them, it was especially important the salic type.
These Pio-Pleistocene Series are the ones that formed the landscape that we can see nowadays when we travel through the Canary Islands. Of course, we must add the erosion process, which modifies the final result. We also have to bear in mind other processes such as the landslides, which provokes the formation of valleys and calderas.
This has been the Canary Islands origin, but…What
has happened with all this volcanic activity?
This is, in short, the Canary Islands origin and evolution. We must add that the volcanic activity has never stopped. Of course, there has never been such an amount of lava ejection, but the thing is that lots of canary volcanos are still active, such as El Teide itself. Successive studies confirm this idea, and the fumaroles that, from time to time, El Teide ejects, are very well known. Nevertheless, we do not have to be worried about it, for there is nothing that can makes us suspect that we are in danger. We only have to enjoy the perks of living in the Canary Islands!
To write this text, the following posts have been taken as reference: Origen y formación de las Islas Canarias, published in GEVIC, and Formación de las Islas Canarias, published in CanariWiki.
Photographs:
Fatured image: Walter Lim (enlace a la licencia)
Text images: Wikipedia