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The Chukchi Plateau or Chukchi Cap is a large subsea formation extending north from the Alaskan margin into the Arctic Ocean. The ridge is normally covered by ice year-round, and reaches an approximate bathymetric prominence of 3,400 m with its highest point at 246 m below sea level. As a subsea ridge extending from the continental shelf of the United States north of Alaska, the Chukchi Plateau is an important feature in maritime law of the Arctic Ocean and has been the subject of significant geographic research. The ridge has been extensively mapped by the USCGC ''Healy'', and by the Canadian icebreaker CCGS ''Louis S. St-Laurent'' (with the ''Healy'') in 2011 and RV ''Marcus Langseth'', a National Science Foundation vessel operated by the Lamont-Doherty Earth Observatory of Columbia University. == Geology == The geologic history of Arctic Ocean basins is a major source of debate among marine geophysicists. The difficulties associated with collecting marine geologic and geophysical data in this remote region has added to the debate on the tectonic history of the Arctic Ocean and the formation of its bathymetric features. The Chukchi Borderland, which comprises the subsea region north of the Alaskan coast as well as the bathymetric highs of the Chukchi Plateau and the adjacent Northwind Ridge, is a continental fragment that is thought to have drifted from the Canadian continental margin.〔http://www.agu.org/books/gd/v006/GD006p0045/GD006p0045.pdf〕 The geomorphology of the region is defined by north-south trending normal faulting –tectonic activity typical of continental rifting. Although there is no consensus as to the pre-rift location of the Chukchi Borderland, its tectonic migration could be attributed to an inferred spreading center indicated by a linear gravity low in the Canada Basin . Sediments transported from the Mackenzie River Delta would have buried the spreading center. The Chukchi Plateau, which could have been connected to Canada in the vicinity of Ellesmere Island, would have rifted along the spreading center to its current location. A competing hypothesis suggests that the Chukchi Plateau may have once been attached to the Siberian shelf. The Chukchi Plateau also shows substantial evidence of pockmarks, which indicates subsurface hydrocarbon activity. 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「Chukchi Plateau」の詳細全文を読む スポンサード リンク
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