Rumurutiite (North West Africa 13518 Meteorite) (Algeria) 3 : 無料・フリー素材/写真
Rumurutiite (North West Africa 13518 Meteorite) (Algeria) 3 / 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 | Rumurutiite (R-chondrite) - North West Africa 13518 Meteorite from Algeria. (cut, polished surface)Chondrites are the most common type of meteorites that fall to Earth. Chondrite classification is moderately complicated, and considers isotopic, chemical, mineralogical, textural, metamorphic, and weathering factors. Chondrites are derived from bodies in the Asteroid Belt that never underwent differentiation. That is, the parent bodies never experienced a heating event sufficient to produce a core, mantle, and crust. All chondrites contain spherical to subspherical to somewhat irregularly shaped structures called chondrules. Chondrules are composed principally of mafic minerals (olivine and pyroxene). Chondrules are nearly the oldest materials in the entire solar system. Chondrites subjected to significant thermal metamorphism some time in their history have chondrules that are partially to almost completely recrystallized.Ordinary chondrites are the most common category of chondrites. Other varieties include carbonaceous chondrites, E-chondrites (enstatite chondrites), R-chondrites (rumurutiites), K-chondrites (kakangariites), F-chondrites (forsterite chondrites), and G-chondrites.The NWA 13518 Meteorite is an R-chondrite, known as a rumurutiite, named after the type example (Rumuruti Meteorite). Compared with ordinary chondrites, rumurutiites are oxidized, olivine rich (and the olivine is iron-rich, rather than magnesium-rich), and have the highest reported oxygen-17 isotope content of any meteorite type. Many rumurutiites are rich in solar gases, and so are interpreted as regolith breccias. The NWA 13518 rock itself has been classified as R4 (= a chondrite with obvious and abundant metamorphosed chondrules and metamorphosed matrix). NWA 13518 samples also have clasts classified as R5 (= a chondrite with metamorphosed chondrules that are present, but not well defined). As such, NWA 13518 is referred to as an "R4-5 chondrite".-----------------------------------Info. on NWA 13518:www.lpi.usra.edu/meteor/metbull.php?sea=NWA+13518&sfo... |
| 撮影日 | 2024-05-12 19:20:20 |
| 撮影者 | James St. John |
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