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The South Sandwich Islands consist
of a chain of eleven main islands that
bend in an arc 240 miles (~400
km) long. The water surrounding the
volcanoes has an average depth of
about 8,500 feet (2,600 m). About 80% of each island is
covered by glaciers. These volcanic
islands are west of the South
Sandwich trench. The map is based on
Barker and Hill (1981).
The islands were first sighted in 1775, but the first landing didn't occur until 1818 when seal hunters visited. The islands are administered by the United Kingdom and claimed by Argentina. The South Sandwich Islands are uninhabited and far away from commercial shipping and air routes. Because high latitude of the islands and the frequent cloudy days photographs by the Space Shuttle astronauts are rare. |
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The South Sandwich
Islands are a volcanic island
arc caused by the
subduction of the South American Plate beneath the South Sandwich Plate. The
South Sandwich plate is one of the smallest geologic plates and is
created at the South
Sandwich spreading center.
This small plate is less than
8 million years old and
moves to the east at
about 7 cm per year. The
volcanic arc is younger than
5 million years. Arrows on the map
show direction of
movement. The map is based on
Barker and Hill (1981).
Basalt makes up at least 70% of the islands. On average, about 60% of each island is made of lava and about 40% by tephra. |
WE NEED YOUR HELP!
If you have any photos of these volcanoes we would
like to borrow them to scan and add to the VolcanoWorld
collection. Thanks!
The islands/volcanoes from south to north:
Baker, P.E., 1968, Comparative volcanology and petrology of the Atlantic
island arcs: Bulletin of Volcanology, v. 32, p. 189-206.
Baker, P.E., 1978, The South Sandwich Islands: III, Petrology of volcanic
rocks. British Antarctic Survey Science Report No. 93.
Baker, P.E., 1990, The South Sandwich Islands in LeMasurier, W.E., and
Thomson, J.W., editors, Volcanoes of the Antarctica Plate and southern
oceans: Washington, DC, American Geophysical Union, p. 361-395.
Barker, P.F., and Hill, I.A., Back-arc extension in the Scotia Sea: Phil.
Trans. R. Soc. London, Series A, v. 300, p. 249-262.
Berninghausen, W.H., and Neumann van Padang, M., 1960, Antarctica:
Catalogue
of the active volcanoes of the world, Rome, IAVCEI, 10, 32 p.
Coombs, D.S., and Landis, C.A., 1966, Pumice from the South Sandwich
eruption of 1962 reaches New Zealand: Nature, v. 209, p. 289-290.
Gass, I.G., Harris, P.G., and Holdgate, M.W., 1963, Pumice eruption in the
area of the south Sandwich Islands: Geol. Mag., v. 100, p. 321-330.
LeMasurier, W.E., and Thomson, J.W., editors, 1990, Volcanoes of the
Antarctica Plate and southern oceans: Washington, DC, American Geophysical
Union, p.487
Leat, P., et al., 2000. Journal of Petrology Volume 41 Number 6 Pages 845-866
Sources of Information--South Sandwich Islands section:
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