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Northwest Africa 14635 | |||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 14635 This is an OFFICIAL meteorite name. Abbreviation: NWA 14635 Observed fall: No Year found: 2009 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 4 approved meteorites classified as Achondrite (brachinite-like). [show all] Search for other: Primitive achondrites, Ungrouped achondrites | ||||||||||||||||||||||||||||||
Comments: | Approved 26 Mar 2022 | ||||||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 111:
Northwest Africa 14635 (NWA 14635) (Northwest Africa) Purchased: 2009 Classification: Brachinite-like achondrite History: Purchased by Chalom Malka in 2009 from a meteorite dealer in Morocco. Physical characteristics: Three stones with weathered fusion crust. Petrography: (D. Sheikh, Cascadia) Sample displays a protogranular texture (Av. grain size=360±230 μm, n=253) predominantly composed of olivine (some grains are elongated and display a notable alignment) (~81 vol. %), orthopyroxene (some regions of the sample display orthopyroxene poikilitically enclosing olivine, chromite, and accessory plagioclase) (~15 vol. %), augite (~3 vol. %), chromite (~1 vol. %), and accessory plagioclase (observed only poikilitically enclosed within either orthopyroxene or chromite), troilite, chlorapatite, merrillite, and Fe-Ni metal (some altered to Fe-hydroxides). A fine-grained intergrowth of orthopyroxene + opaque minerals is observed along the margins of some olivine grains. Geochemistry: Olivine (Fa28.0±0.7, range Fa26.7-29.0, CaO=<0.1 wt. %, Cr2O3=<0.1 wt. %, Fe/Mg=0.39±0.01, Fe/Mn=54±2, n=17), Orthopyroxene (Fs23.9±1.5Wo1.9±0.5, range Fs20.5-24.7Wo0.8-2.2, Fe/Mn=36±3, n=13), Augite (Fs9.8±0.1Wo43.5±0.1, range Fs9.7-9.8Wo43.4-43.5, Al2O3=0.7±0.1 wt. %, Cr2O3=0.9±0.1 wt. %, Fe/Mn=25±2, n=2), Plagioclase (An35.2±0.8Or1.1±0.1, range An34.4-35.7Or1.1-1.2, n=3), Chromite (Cr#=76.1±0.1, Mg#=23.9±2.4, TiO2=1.3±0.1 wt. %, n=5). Classification: Achondrite (brachinite-like). While the overall texture, mineralogy, and mineral compositions of the sample are similar to brachinites, the high modal abundance of orthopyroxene, the presence of poikilitic pyroxene-rich areas, the near absence of plagioclase feldspar observed in the sample, the low abundance of CaO in olivine, the low Fe/Mg-Fe/Mn molar ratios of olivine, the fine-grained intergrowth of orthopyroxene + opaque minerals observed at olivine grain boundaries, and the more magnesian compositions of olivine and orthopyroxene indicate that this sample is representative of a brachinite-like achondrite (Goodrich et al., 2017), having similarities to NWA 595, NWA 1500, and NWA 5400. Specimens: 14.5 g at Cascadia, main mass with Chalom Malka | ||||||||||||||||||||||||||||||
Bibliography: |
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Data from: MB111 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. 111, in preparation (2022)
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Photos: |
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Geography: |
Statistics: This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names) |