Bouvetøya
- ISS002-E-7002
- 01 June 2001
- 12:34 UTC
Bouvetøya (formerly known, and often still referred to, as Bouvet Island), is a distant overseas territory of Norway. It lies in the far southern reaches of the Atlantic Ocean 2,500 km southwest from Cape Town and 1,600 km southeast from Gough Island — making it one of the most isolated of the sub-Antarctic islands. The Queen Maud Land region of Antarctica lies 1,600 km directly southwards from Bouvetøya. Bouvetøya measures 10 km in length and 5 km in width, covering an area of 58.5 km².
The island is the emergent summit of an active shield volcano located upon the Atlantic-Indian ridge — the southernmost sections of the Mid-Atlantic Ridge — in a region where the three tectonic plates of Africa, South America, and Antarctica meet. The last volcanic activity on the island is thought to have taken place around 2,000 years ago and produced the lava flows observed at cape Meteor on the eastern side of the island.
Bouvetøya has a flat to sloping profile, rising to a height of 780 m above sea level at the peak known as Olavtoppen, and rises sharply from sea level in high cliffs of rock or ice (100 to 350 m in height). The coastline is steepest on the northern, western and southwestern sides; small beaches composed of black volcanic sand or shingle are found on the eastern side of the island. The most extensive flat coastal area is the rocky and gravelly Nyrøysa platform — thought to be the result of a landslide that took place sometime in the late 1950's.
Most of Bouvetøya is blanketed in a thick ice cap of at least 100 m in thickness, as well as by glaciers such as those of the Posadowsky Glacier (located to the west of Cape Valdivia) and Christensen Glacier (located near Cato Point on the southwest). In all, over 90 per cent of the island is permanently covered in ice. Where the ice cap does not fall directly to sea, it terminates above the small beaches of the east coast in tall ice cliffs. Near the centre of the island is a 3.5 km wide caldera known as the Wilhelm II Plateau, which is breached on the northwestern wall.
Vegetation on the island is limited by ice and severe weather, and is found primarily on rocky coastal cliffs, beaches and on ridges that emerge through the ice cap of the interior. It consists solely of non-vascular species such as lichens, mosses and bryophytes. 12 species of seabird are known to breed on the island including large numbers of Macaroni (Eudyptes chrysolophus) and Chinstrap (Pygoscelis antarctica) penguins. The Antarctic fur seal (Arctocephalus gazella) also has breeding colonies on Bouvetøya's beaches. The island was designated as a nature reserve in 1971.
image: earth sciences and image analysis laboratory, nasa johnson space center