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Greenland's Grand Canyon or Grand Canyon of Greenland is a tentative canyon of record length discovered underneath the Greenland ice sheet as reported in the journal ''Science'' on 30 August 2013 (submitted 29 April 2013), by scientists from the University of Bristol, University of Calgary, and University of Urbino, who described it as a mega-canyon.〔(【引用サイトリンク】url=http://edition.cnn.com/2013/08/29/world/europe/greenland-megacanyon/index.html )〕〔Jonathan L. Bamber, Martin J. Siegert, Jennifer A. Griggs, Shawn J. Marshall, and Giorgio Spada, "Paleofluvial Mega-Canyon Beneath the Central Greenland Ice Sheet", ''Science'', 30 August 2013, Vol. 341 no. 6149, pp. 997-999. 〕 Ice-penetrating radar data collected during NASA's Operation IceBridge showed a huge subglacial canyon〔Oskin, Becky, "('Grand Canyon of Greenland' discovered under ice sheet )", NBC News, August 29, 2013〕 running from the central region of the island northward into the Arctic Ocean, to the fjord of the Petermann Glacier. The canyon is likely to have influenced basal water flow from the ice sheet interior to the margin. Jonathan Bamber, a geographer at University of Bristol, stated, "The distinctive V-shaped walls and flat bottom suggests water carved the buried valley, not ice."〔 The canyon is more than long, up to deep and wide, making it the longest canyon discovered on the Earth to date.〔 There are, however, many canyons—including Arizona's Grand Canyon and Xizang's Yarlung Tsangpo Grand Canyon, previously the world's longest—that are deeper. The canyon predates ice sheet inception and has influenced basal hydrology in Greenland over past glacial cycles. It is estimated to be at least four million years old, possibly millions of years older. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Greenland's Grand Canyon」の詳細全文を読む スポンサード リンク
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