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A Dreikanter is a type of ventifact that typically forms in desert or periglacial environments due to the abrasive action of blowing sand.〔Wade, A. 1910. On the formation of dreikanter in desert regions. The Geological Magazine, Decade V, 7(9):394-398.〕 Dreikanters exhibit a characteristic three-faced pyramidal shape. The word ''Dreikanter'' is a German word meaning "three-edged."〔(WeatherTalk - Jargon )〕 A dreikanter is not to be confused with a zweikanter, which has only two sides, or an einkanter, which has only one windblown side. 〔Greeley, R., N. T. Bridges, R. O. Kuzmin, and J. E. Laity, Terrestrial analogs to wind-related features at the Viking and Pathfinder landing sites on Mars, J. Geophys. Res., 107(E1), 10.1029/2000JE001481, 2002. 〕 Most places on the planet have several weathering processes acting at the same time, so finding good examples of Dreikanters is often difficult. Antarctica is a good location for finding such ventifacts since wind is usually the only active weathering agent. Many specimens in the Northeastern United States were formed during the Pleistocene era when the absence of vegetation made for little cover from wind-blown sediment. ==Common Features== Some common features of Dreikanters include fluting, high polish, sharp ridges, pits, grooves, and helical forms. 〔Greeley, R., N. T. Bridges, R. O. Kuzmin, and J. E. Laity, Terrestrial analogs to wind-related features at the Viking and Pathfinder landing sites on Mars, J. Geophys. Res., 107(E1), 10.1029/2000JE001481, 2002.〕 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「Dreikanter」の詳細全文を読む スポンサード リンク
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