The archipelago of Madeira is located 520 km (280 nmi) from the African coast and 1,000 km (540 nmi) from the European continent (approximately a one-and-a-half hour flight from the Portuguese capital of Lisbon). It is found in the extreme south of the Tore-Madeira Ridge, a bathymetric structure of great dimensions oriented along a north-northeast to south-southwest axis that extends for 1,000 kilometres (540 nmi). This submarine structure consists of long geomorphological relief that extends from the abyssal plain to 3500 metres; its highest submersend point is at a depth of about 150 metres (around latitude 36ºN). The origins of the Tore-Madeira Ridge are not clearly established, but may have resulted from a morphological buckling of the lithosphere.
The island of Madeira is at the top of a massive shield volcano that rises about 6 km (20,000 ft) from the floor of the Atlantic Ocean, on the Tore underwater mountain range. The volcano formed atop an east-west rift in the oceanic crust along theAfrican Plate, beginning during the Miocene epoch over 5 million years ago, continuing into the Pleistocene until about 700,000 years ago. This was followed by extensive erosion, producing two large amphitheatres open to south in the central part of the island. Volcanic activity later resumed, producing scoria cones and lava flows atop the older eroded shield. The most recent volcanic eruptions were on the west-central part of the island only 6,500 years ago, creating more cinder cones and lava flows.
Madeira Island represents 93% of the archipelago’s area, with 90% of the landmass above 500 m. It is the largest island of the group with an area of 741 km2 (286 sq mi), a length of 57 km (35 mi) (from Ponte de São Lourenço to Ponte do Pargo), while approximately 22 km (14 mi) at its widest point (from Ponte da Cruz to Ponte São Jorge), with a coastline of 150 km (90 mi). It has a mountain ridge that extends along the centre of the island, reaching 1,862 meters (6,109 feet) at its highest point (Pico Ruivo), while much lower (below 200 meters) along its eastern extent. The primitive volcanic foci responsible for the central mountainous area, consisted of the peaks: Ruivo (1862 meters), Torres (1851 meters), Arieiro (1818 meters), Cidrão (1802 meters), Cedro (1759 meters), Casado (1725 meters), Grande (1657 meters), Ferreiro (1582 meters). At the end of this eruptive phase, an island circled by reefs was formed, its marine vestiges are evident in a calcareous layer in the area of Lameiros, in São Vicente (which was later explored for calcium oxide production). Sea cliffs, such as Cabo Girão, valleys and ravines extend from this central spine, making the interior generally inaccessible. Daily life is concentrated in the many villages at the mouths of the ravines, through which the heavy rains of autumn and winter usually travel to the sea. A long, narrow, and comparatively low rocky promontory (Paul da Serra) forms the western extremity of the island, on which lies a tract of calcareous sand known (1300–1500 meters). It is a fossil bed, which contains shells and numerous bodies resembling the roots of trees, probably produced by infiltration.