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Northwest Africa 11993 | |||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 11993 This is an OFFICIAL meteorite name. Abbreviation: NWA 11993 Observed fall: No Year found: 2006 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||
Classification history: |
This is 1 of 629 approved meteorites classified as Ureilite. [show all] Search for other: Achondrites, Ureilites | ||||||||||||||||||||||||||
Comments: | Approved 9 Oct 2018 | ||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 107:
Northwest Africa 11993 (NWA 11993) (Northwest Africa) Purchased: 2006 Sept Classification: Ureilite History: Samples were donated to Cascadia by Mr. Fred Olsen in July 2012. Physical characteristics: Interior and slightly shiny exterior have a relatively uniform dark-gray color with occasional light reddish-brown patches. Petrography: (A. Ruzicka, S. Goudy, Cascadia) Composed chiefly of olivine and pigeonite grains roughly 1 mm across, often separated by fine-grained materials, cracks, or Fe-hydroxide weathering product. No metal or sulfide minerals were found. Shock stage U-S4 (Stöffler et al. 2018) Geochemistry: (A. Ruzicka, M. Hutson, Cascadia) Cores of olivine grains have ferroan olivine (Fa22.6±0.7, N = 38) and rims are more magnesian (Fa15.6±3.6, N = 9). Pigeonite (Fs17.1±3.8Wo11.1±3.5, , N = 28) shows less prominent magnesian rims. Classification: Achondrite (ureilite). Silicate grain cores and rims were largely unaffected by weathering, but presence of hydroxide and reddish staining indicates some weathering occurred. Specimens: A total of 20.6 g and 1 thin section are on deposit at Cascadia. Mr. McKenzie holds the main mass. | ||||||||||||||||||||||||||
Bibliography: |
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Data from: MB107 Table 0 Line 0: |
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Institutions and collections |
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011) |
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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 9111 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) |