- West Antarctic Rift
The West Antarctic Rift is a major, active rift valley lying between East and
West Antarctica . It encompasses theRoss Sea , the area under theRoss Ice Shelf and a part of West Antarctica. Its evolution is due to lithospheric thinning of the non-craton ic area of West Antarctica.Because, apart from peaks of the
Transantarctic Mountains that protrude above the ice, the region is covered by the vastWest Antarctic Ice Sheet , it is very difficult to explore thegeology of the West Antarctic Rift, so that it is less well known than other major rift valleys. It is known, however, that like theEast African Rift , the West Antarctic Rift is actually a number of much shorter rifts that cross Antarctica. There is also a sharp division between older, broaderPaleogene rifts including the Ross Sea Basin and the younger, narrower Terror Rift. There are also a large number of failed rifts extending as far asBerkner Island .Although many rifts within the West Antarctic Rift system are no longer active, it is now known that West Antarctica is moving away from the East Antarctic Craton in a north/northeasterly direction (approximately in the direction of the
South Georgia Islands at a rate of about 2 mm per year or 500,000 years per kilometre.The West Antarctic Rift is the source of all the recently active volcanoes within Antarctica, and of most of the major Antarctic mountain systems outside the
Antarctic Peninsula . It is also believed to have a major influence on ice flows in West Antarctica, because fast moving ice streams are believed [http://www.ig.utexas.edu/research/projects/wais/wais.htm?PHPSESSID=def1b9] to be influenced by the lubrication provided by water-saturatedtill , which some argue could help cause breakup of the ice sheet ifglobal warming accelerates.External links
* [http://www.ldeo.columbia.edu/~mstuding/tam_map_large.html Map of the West Antarctic Rift System and Transantarctic Mountains]
* [http://www.ipy.org/development/ideas/national/idea249.pdf Geodynamics of the West Antarctic Rift System (WARS)]
* [http://www.geosc.psu.edu/~pwinberr/Site/J%20Paul%20Winberry_files/WinAnanGeology.pdf Crustal structure of the West Antarctic Rift System]
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