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| Northwest Africa 11857 | |||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 11857 This is an OFFICIAL meteorite name. Abbreviation: NWA 11857 Observed fall: No Year found: 2018 Country: (Northwest Africa) Mass:  580 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 522 approved meteorites classified as Diogenite. [show all] Search for other: Achondrites, Diogenites, and HED achondrites | ||||||||||||||||||||||||||||||
| Comments: | Approved 8 Jul 2018 | ||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 107:
Northwest Africa 11857 (NWA 11857) Northwest Africa Purchased: 2018 Classification: HED achondrite (Diogenite) History: One stone weighing 580 g was found in Morocco prior to 2018. Steve Arnold purchased the sample from a meteorite dealer while at the 2018 Tucson Gem and Mineral Show. Physical characteristics: The uncrusted sample has a weathered orangish-yellow exterior and yellowish-orange interior that is brecciated and friable. The cut face shows angular-subrounded clasts up to 5 mm in the long dimension. Petrography: Description and classification (A. Love, App): Sample is a breccia composed of diogenitic lithic fragments (with average grainsize of 681 μm) and coarser grained (~1287 μm) cataclastic clasts mixed within a comminuted host of similar materials. Lithic clasts are composed of interlocking, orthopyroxenes, which share 120º grain boundaries. Orthopyroxenes contain CPX inclusions and exsolution lamellae (up to 0.5mm) within crystals. Additional minerals are Si polymorphs, chromite, FeS and rare Ni-free iron metal. Geochemistry: (A. Love, App) Low-Ca pyroxene host Fs26.2±0.6 Wo2.8±0.7 (Fs26.2-28.0Wo1.8-3.6, FeO/MnO=26.3-27.6 , N=12); high-Ca pyroxene inclusions and exsolution lamellae Fs10.6±0.5Wo44.0±1.2 (Fs9.9-11.6Wo41.9-45.7, FeO/MnO=20.1-21.2 N=6) Classification: HED (monomict diogenite breccia). Textures, FeO/MnO and Fs compositions of pyroxenes indicate this sample is a diogenite. Specimens: Steve Arnold holds the main mass. One 20 g endcut, several fragments and a polished thin section are on deposit at App. | ||||||||||||||||||||||||||||||
| Data from: MB107 Table 0 Line 0: |
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| Institutions and collections |
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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| Geography: |
Statistics: This is 1 of 9710 approved meteorites from (Northwest Africa) (plus 1853 unapproved names) | ||||||||||||||||||||||||||||||
| Also see: |
This lists the most popular meteorites among people who looked up this meteorite.
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| Revision history: |
This lists important revisions made to data for this record.
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