Volcanic rock arches, Barranco de la Negra, Gran Canaria, Canary Islands, Spain. Most of Gran Canaria was formed by a series of volcanic eruptions around 14 to 9 million years ago, in the Miocene Period. These eruptions lasted around 200,000 years, emitting an estimated 1,000 cubic km of rock. Further erosion and eruptions over millions of years led to the present land form