Peridotite mantle xenoliths in phonotephrite (Peridot Mesa Flow, Middle Pleistocene, 580 ka; Peridot Mesa, San Carlos Volcanic Field, Arizona, USA) 25 : 無料・フリー素材/写真
Peridotite mantle xenoliths in phonotephrite (Peridot Mesa Flow, Middle Pleistocene, 580 ka; Peridot Mesa, San Carlos Volcanic Field, Arizona, USA) 25 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Peridotite mantle xenoliths in vesicular phonotephrite from the Pleistocene of Arizona, USA.Green = peridotiteGray = phonotephrite host rock“Peridot” is a gemological term for gem-quality forsterite olivine, but it does not differ in any chemical sense from ordinary olivine. Gem-quality olivine is known from several places on Earth, including Peridot Mesa in southeastern Arizona, USA. The volcanic rocks making up Peridot Mesa are gray, vesicular phonotephrites (formerly misidentified as basanites) of the Peridot Mesa Flow, a 3 to 35 meter thick lava flow erupted during the Middle Pleistocene (~580,000 years ago). The Peridot Mesa lavas have common greenish-colored xenoliths derived from the mantle. The xenoliths are ultramafic, crystalline-textured, intrusive igneous rocks principally composed of olivine and/or pyroxene. Specific Peridot Mesa xenolith lithologies include spinel lherzolite, dunite, harzburgite, clinopyroxenite, websterite, and orthopyroxenite. Stratigraphy: Peridot Mesa Flow, middle Middle Pleistocene, ~580 ka Locality: Peridot Mesa, San Carlos Volcanic Field, San Carlos Apache Reservation, southeastern margin of Gila County, southeastern Arizona, USA |
| 撮影日 | 2022-03-28 10:49:10 |
| 撮影者 | James St. John |
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