Gran Canaria GeologyThe Canary Islands are a volcanic archipelago which lies off the coast of north-western Africa.
Although there is some debate over the cause of the Volcanic Activity in this area, the most probable theory is that the Islands were formed by the dual processes of a Hot Spot (or Mantle Plume) and the proximity to the Geologically Active Atlas Mountains.
The Hot Spot theory suggests that, as the diverging African and South American tectonic plates separate, the Canary Islands were formed as they crossed a mantle plume that sent molten rock to the surface. The fact that the Canary Islands get older as they go from West to East (Lanzarote and Fuerteventura are the oldest) supports this theory.
The origins of the dramatic scenery of Gran Canaria began about 15 million years ago with the first submarine building stages of the Gran Canaria Volcano. The first sub-aerial activity took place about 14 Million Years ago. This shield-building phase (growth phase) continued until about 9 Million Years ago when there was a massive collapse that formed the 20km in diameter Tejeda Caldera. While this Caldera isn't as clearly defined today, parts of it's enormous walls can still be seen.
After the collapse, the Caldera gradually filled up with Lava and other volcanic material over the next few million years. This period was followed by 3 million years of volcanic inactivity and erosion.
The next major stage, between 4.5 and 3.5 Million years ago, was characterised by explosive eruptions. This was again followed by a period of erosion.
Gran Canaria is now in it's Post-Erosional stage with it's last eruption taking place at Bandama about 2000 years ago.
Roque Nublo and the other monolithic "Roques" in the centre of the Island are the exposed remnants of a huge lava field that once covered this area.