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Northwest Africa 11858 | |||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 11858 This is an OFFICIAL meteorite name. Abbreviation: NWA 11858 Observed fall: No Year found: 2008 Country: Morocco Mass: 454 g | ||||||||||||||||||||||||
Classification history: |
This is 1 of 451 approved meteorites classified as Howardite. [show all] Search for other: Achondrites, HED achondrites, and Howardites | ||||||||||||||||||||||||
Comments: | Approved 8 Jul 2018 | ||||||||||||||||||||||||
Writeup |
Writeup from MB 107:
Northwest Africa 11858 (NWA 11858) Morocco Purchased: 2008 Classification: HED achondrite (Howardite) History: The meteorite was purchased at the Munich show in 2008 from a Moroccan meteorite dealer from Rissani. Physical characteristics: The main mass is approximately 4 × 4 × 10 cm, and is almost completely covered in fusion crust, some of which is dark brown and glassy with flow lines. Minor evidence of terrestrial weathering is present as red-brown straining and adhered dust. Cut surfaces reveal numerous, mostly gray clasts set in a fine-grained, light-gray matrix. Petrography: (C. Herd and J. Hamilton, UAb) Well-consolidated breccia of clasts up to 5 mm in longest dimension of diogenite (~25 vol%), unequilibrated eucrite (~10 vol%), equilibrated eucrite (~10 vol%), cumulate gabbroic eucrite (~10 vol%), and impact melt, as well as grains of anorthitic plagioclase, olivine, chromite, sulfide, and FeNi metal. All plagioclase has been transformed to maskelynite, and strong mosaicism is common. Fine-grained recrystallized areas of some gabbroic eucrite clasts indicate shock melting. Geochemistry: (C. Herd, UAb) Diogenite orthopyroxene Fs27±3Wo2.6±0.8, Fe/Mn=32±2, n=23, eucrite pigeonite average Fs48±10Wo6±3, Fe/Mn=32±2, range Fs32-63, n=32, eucrite augite Fs40±10Wo28±10, Fe/Mn=32±1, n=10; plagioclase An88±3Ab11±3Or0.5±0.3, n=21; high-Ti (15 wt% TiO2) and low-Ti (0.8 wt% TiO2) chromite. Classification: Achondrite (howardite) Specimens: Type specimen of 21.3 g, including one thin section, is at UAb. Main mass at JTESM. | ||||||||||||||||||||||||
Data from: MB107 Table 0 Line 0: |
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Institutions and collections |
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011) JTESM: Joshua Tree Earth And Space Museum PO BOX 101, Lakeville, IN 46536, United States (institutional address; updated 17 Dec 2016) |
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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 2068 approved meteorites from Morocco (plus 31 unapproved names) (plus 1 impact crater) | ||||||||||||||||||||||||
Also see: |
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Revision history: |
This lists important revisions made to data for this record.
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