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- Mima Mounds sind relativ niedrige, hügelartige Erhebungen, die aus losen, ungeschichteten Sedimenten aufgebaut werden. Die natürlich entstandenen Strukturen entsprechen einem sehr mächtigen A-Horizont. Ihre Entstehung ist nach wie vor nicht restlos geklärt, obwohl mehrere Erklärungsansätze bestehen. (de)
- Mima mounds /ˈmaɪmə/ are low, flattened, circular to oval, domelike, natural mounds that are composed of loose, unstratified, often gravelly sediment that is an overthickened A horizon. These mounds range in diameter from 3 to more than 50 m; in height 30 cm to greater than 2 m; and in density from several to greater than 50 mounds per hectare, at times forming conspicuous natural patterns. Mima mounds can be seen at the Mima Mounds Natural Area Preserve in Washington state. "Mima" is a name derived from a Chinook Jargon term meaning "a little further along" or "downstream". Theories for the origin of Mima mounds include burrowing by pocket gophers; accumulation of wind-blown (aeolian) sediments around vegetation to form coppice dunes or nebkhas; seismic ground shaking by major earthquakes, though none have been observed to form Mima mounds; and shrinking and swelling of clays in hog-wallow or gilgai landforms. Though the definitive Mima mounds are common in North America, it has not been shown that all North American mounds result from the same causes. Superficially similar phenomena occur on all continents, and the proposed causal factors do not occur in all regions that have been studied. Nor is it clear that all such mounds really are the same, either physically or functionally; for example, the so-called fairy circles of Southern Africa tend to be less mound-like and occur in different climatic and ecological conditions from mima mounds. Furthermore, it has been argued that the possibly distinct heuweltjies of the South Western Cape region of South Africa are of an origin far different from either. (en)
- 美馬塚(英語:Mima mounds;/ˈmaɪmə/)是一種覆蓋大面積土地的圓形土丘所形成的地質異常現象,由一組矮小、平坦、圓至鵝蛋形的圓土墩,由鬆散的、非層化的沉積物組成。多見於北美地區及非洲南部,當中以美國西北部華盛頓州的最為知名,但其實在世界各地都有發現,只是先前這些土丘被以為是由地鼠(gopher)造成的。在非洲南部,這些土墩被稱為「仙子圓圈」(fairy circles)。 美馬塚的高度從30公分到2米,直徑從3米到50米,而密集程度從每公頃數個到50個不等。總數最多的地區達數百萬之多,在地面上延伸許多公里。美馬塚的形成原因多年來一直困惑科學家,其神秘之處就在於到現在為止還沒有人真正知道它們是如何形成。在過去一、二百年間,人們認為它們是美國原住民的墓塚,或是由地震或冰川所造成,有些人甚至主張是外星人所為。也有人認為是由風吹、水淹、甚或由囊鼠科物種挖掘而形成。 (zh)
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- Panorama of Mima Mounds in Thurston County. (en)
- Panorama of Mima Mounds near Olympia, WA. (en)
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- Mima Mounds sind relativ niedrige, hügelartige Erhebungen, die aus losen, ungeschichteten Sedimenten aufgebaut werden. Die natürlich entstandenen Strukturen entsprechen einem sehr mächtigen A-Horizont. Ihre Entstehung ist nach wie vor nicht restlos geklärt, obwohl mehrere Erklärungsansätze bestehen. (de)
- 美馬塚(英語:Mima mounds;/ˈmaɪmə/)是一種覆蓋大面積土地的圓形土丘所形成的地質異常現象,由一組矮小、平坦、圓至鵝蛋形的圓土墩,由鬆散的、非層化的沉積物組成。多見於北美地區及非洲南部,當中以美國西北部華盛頓州的最為知名,但其實在世界各地都有發現,只是先前這些土丘被以為是由地鼠(gopher)造成的。在非洲南部,這些土墩被稱為「仙子圓圈」(fairy circles)。 美馬塚的高度從30公分到2米,直徑從3米到50米,而密集程度從每公頃數個到50個不等。總數最多的地區達數百萬之多,在地面上延伸許多公里。美馬塚的形成原因多年來一直困惑科學家,其神秘之處就在於到現在為止還沒有人真正知道它們是如何形成。在過去一、二百年間,人們認為它們是美國原住民的墓塚,或是由地震或冰川所造成,有些人甚至主張是外星人所為。也有人認為是由風吹、水淹、甚或由囊鼠科物種挖掘而形成。 (zh)
- Mima mounds /ˈmaɪmə/ are low, flattened, circular to oval, domelike, natural mounds that are composed of loose, unstratified, often gravelly sediment that is an overthickened A horizon. These mounds range in diameter from 3 to more than 50 m; in height 30 cm to greater than 2 m; and in density from several to greater than 50 mounds per hectare, at times forming conspicuous natural patterns. Mima mounds can be seen at the Mima Mounds Natural Area Preserve in Washington state. "Mima" is a name derived from a Chinook Jargon term meaning "a little further along" or "downstream". (en)
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- Mima Mounds (de)
- Mima mounds (en)
- 美馬塚 (zh)
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