Geology

Considering by their age or by their petrography, there are 2 volcanic groups in the archipelago:

Madeira-Desertas-Porto Santo group

This group of volcanic islands is interpreted as a long-lived ‘hot spot’ which rose about 5300 metres from the mantle of Madeira Abyssal Plain, which is part of the African plate.

Volcanic eruptions combined with periods of tectonic uplift gave origin to the present islands with the oldest being Porto Santo with around 15 million years. Madeira is thought to be around 6 million years old though its last volcanic activity dates from 6 to 7 thousand years ago. Although volcanic activity appears extinct, there has been some seismic records, nothing major, but sometimes enough to trigger landslides or even some mass movement of superficial deposits.

The Selvagens group

This sub-archipelago has greater affinity with the Canary islands as they date from 24 to 27 million years ago. It presents volcanic breccias which built the volcanic complex from which these islands represent the highest and emerging areas.