Madeira Island

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Madeira
Madeira OnEarth WMS.png
Satellite image of Madeira
Madeira in its region.svg
Location of Madeira
Geography
Location Atlantic Ocean
Coordinates 32°39′4″N 16°54′35″W / 32.65111°N 16.90972°W / 32.65111; -16.90972Coordinates: 32°39′4″N 16°54′35″W / 32.65111°N 16.90972°W / 32.65111; -16.90972
Archipelago Madeira Archipelago
Adjacent bodies of water Atlantic Ocean
Area 740.7 km2 (286.0 sq mi)
Highest point Pico Ruivo
1,862 m (6,109 ft)
Administration
Portugal
Autonomous Region Autonomous Region of Madeira
Capital and largest City Funchal
Demographics
Population 267,785 (2011)

Madeira is a Portuguese island, and is the largest and most populous of the Madeira Archipelago. It has an area of 740.7 km², including Ilhéu de Agostinho, Ilhéu de São Lourenço, Ilhéu Mole (northwest). As of 2011, Madeira had a total population of 262,456.

It 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[1][2] in the oceanic crust along the African Plate, beginning during the Miocene epoch over 5 million years ago, continuing into the Pleistocene until about 700,000 years ago.[3] 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.[3]

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 metres (6,109 feet) at its highest point (Pico Ruivo), while much lower (below 200 metres) along its eastern extent. The primitive volcanic foci responsible for the central mountainous area, consisted of the peaks: Ruivo (1,862 m), Torres (1,851 m), Arieiro (1,818 m), Cidrão (1,802 m), Cedro (1,759 m), Casado (1,725 m), Grande (1,657 m), Ferreiro (1,582 m). 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.[4] 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.[5]

See also[edit]

  • Madeira, the archipelago and Autonomous Region named after Madeira Island

References[edit]

  1. ^ Geldemacher et al., 2000
  2. ^ Ribeiro, 2001
  3. ^ a b "Madeira". Global Volcanism Program. Smithsonian Institution. 
  4. ^ "MadeiraHelp.com". MadeiraHelp.com. 22 February 1999. Archived from the original on 31 July 2010. Retrieved 30 July 2010. 
  5. ^ Robert White, 1851, p.4