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| Northwest Africa 3164 | |||||||||||||||
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| Basic information | Name: Northwest Africa 3164 This is an OFFICIAL meteorite name. Abbreviation: NWA 3164 Observed fall: No Year found: 2004 Country: (Northwest Africa) Mass:  928 g | ||||||||||||||
| Classification history: |
This is 1 of 40 approved meteorites classified as Angrite. [show all] Search for other: Achondrites, Angrites | ||||||||||||||
| Comments: |
Approved 16 Jan 2006 Revised 3 Feb 2006: Revised writeup | ||||||||||||||
| Writeup |
Writeup from MB 90:
Northwest Africa 3164 Morocco or Algeria Find: August 2004 Achondrite (angrite) History: In August 2004, A. Aaronson purchased many individual dark brown stones totaling 928 g from nomads in Rabat. Petrography: (T. Bunch and J. Wittke, NAU; A. Irving and S. Kuehner, UWS) All stones have irregularly distributed, larger yellowish plagioclase grains exhibiting a luster. The overall texture is granular, but there are large porphyroclasts of anorthite, spinel, and polygranular olivine. There are clinopyroxene-spinel symplectites around anorthite porphyroclasts in contact with olivine, and anorthite also occurs as narrow (10–20 µm wide) coronas around spinel grains adjacent to clinopyroxene. Geochemistry: The major minerals are Ca-rich olivine (Fa39.1–41.2; FeO/MnO = 62–84; CaO = 1.2–1.8 wt%), Al,Ti-bearing diopside (Fs10.3Wo52; FeO/MnO = 130–142; Al2O3 = 6–7, TiO2 = 1–1.6 [both wt%]), minor Cr-bearing pleonaste spinel (Mg/(Mg+Fe) = 45.7, Al2O3 = 59.7, Cr2O3 = 4.7 [both wt%]), almost pure anorthite (<0.02 wt% Na2O), and accessory kamacite and troilite. No kirschsteinite or orthopyroxene was found. Primary metal is partly replaced by limonite, which also occurs along grain boundaries. Classification: Achondrite (angrite). Note: The sample may be paired with NWA 2999. Specimens: A 21 g type specimen and one polished thin section are on deposit at NAU. Boswell holds the main mass. Writeup from MB 91: Northwest Africa 3164 Algeria Find: 2004 Achondrite (angrite) History: A. Aaronson purchased a bag of stones in Rabat, Morocco, in August 2004. T. Boswell then purchased these stones in Denver, Colorado, in September 2005. Physical characteristics: A total of 48 stones with a combined mass of 928 g are all dark brown in color and without fusion crust. Petrography (T. Bunch and J. Wittke, NAU; A. Irving and S. Kuehner, UWS) All stones have irregularly distributed larger yellowish plagioclase grains exhibiting a schiller luster. The major minerals are Ca-rich olivine, diopside, Cr-bearing pleonaste spinel with subordinate anorthite and spinel and accessory kamacite and troilite. No kirschsteinite or orthopyroxene was found. Primary metal is partly replaced by limonite, which also occurs along grain boundaries. The overall texture is protogranular, but there are large porphyroclasts of anorthite, spinel, and polygranular olivine. There are clinopyroxene-spinel symplectites around anorthite porphyroclasts in contact with olivine, and anorthite also occurs as narrow (10–20 µm wide) coronas around spinel grains adjacent to clinopyroxene (Kuehner et al. 2006). Mineral compositions and geochemistry: Ca-rich olivine (Fa39.1–41.2; FeO/MnO = 62–84, CaO = 1.2–1.8 wt%), Al-Ti-bearing diopside (Fs10.3Wo52; FeO/MnO=130–142, Al2O3 = 6–7, TiO2 = 1–1.6 [both wt%]), Cr-bearing pleonaste spinel (Mg/[Mg + Fe] = 45.7, Al2O3=59.7, Cr2O3=4.7 [both wt%]). Classification: Achondrite (angrite). The characteristic textures and mineral compositions indicate that this material is likely paired with NWA 2999. Type specimens: A total of 21 g and one polished thin section are on deposit at NAU. Boswell holds the main mass. | ||||||||||||||
| Data from: MB90 Table 2 Line 195: |
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| Institutions and collections |
NAU: Geology, Bldg 12
Knoles Dr
Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012) UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012) Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 90, MAPS 41, 1383-1418 (2006) Published in Meteoritical Bulletin, no. 91, MAPS 42, 413-466 (2007)
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| Photos: |
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| Geography: |
Statistics: This is 1 of 9111 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) | ||||||||||||||