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The term strewnfield indicates the area where meteorites from a single fall are dispersed.〔''Introduction to Planetary Science: The Geological Perspective''. Gunter Faure, Teresa M. Mensing. Springer, 2007. (page 118 )〕 It is also often used with tektites produced by large meteorite impact.〔''Tektites in the geological record: showers of glass from the sky''. Gerald Joseph Home McCall. Geological Society of London, 2001. (page 10 )〕 ==Formation== There are two strewnfield formation mechanisms: # Mid-air fragmentation: when a large meteoroid enters the atmosphere it often fragments into many pieces before touching the ground due to thermal shock. This mid-air explosion causes the dispersion of the material over a large oval-shaped area. The orientation of this oval is determined by the flight path of the meteoroid. When multiple-explosions occur, the material can be found in several overlapping ovals. # Impact fragmentation: when there is almost no mid-air fragmentation the fragmentation can occur upon impact. In this case the strewnfield shape can be different, usually circular. (e.g. Canyon Diablo at Meteor Crater; Australasian strewnfield) 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「Strewn field」の詳細全文を読む スポンサード リンク
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