The Canary Islands are a volcanic island chain off the northwest coast of Africa. Current geologic evidence suggests that this Spanish archipelago developed (and continues to form) above a mantle plume, commonly known as a hotspot. Erupting through Jurassic oceanic crust that formed as the Atlantic Ocean opened, 150 million years ago (MYA), the base of the oldest islands began to take shape during the Cretaceous Period, some 80 MYA, and finally emerged from the sea during the Miocene Period, about 20 MYA. Mt. Teide, 12,200 feet, rises on the island of Tenerife; the highest peak in Spanish territory, it is also the third tallest volcano on the planet.
The Canary archipelago stretches for 500 km, aligned ENE to WSW; the oldest islands, just 100 km off the African coast lie at the northeast end of the chain while the youngest island, El Hierro, just 1.2 million years old, is at the southwest end of the island group. This past summer, earthquake activity began to increase on El Hierro as a new island grew just 7 km off its southern shore; now less than 70 meters from the surface, the newest Canary island spews seawater and volcanic debris into the air and threatens communities on El Hierro with the potential of an explosive eruption.
Like the Hawaiian Ridge, which has developed as the Pacific Plate moves to the WNW across a mantle plume, the Canaries are high points on a volcanic ridge that has formed as the Atlantic province of the African Plate is moving ENE above a similar hotspot. As a new Hawaiian island forms off the southeast coast of the Big Island, a new Canary Island appears at the southwest end of its parent archipelago.
