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| Northwest Africa 13955 | |||||||||||||||||||||||||||||||
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| Basic information | Name: Northwest Africa 13955 This is an OFFICIAL meteorite name. Abbreviation: NWA 13955 Observed fall: No Year found: 2020 Country: Algeria Mass:  1760 g | ||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 128 approved meteorites classified as Achondrite-ung. [show all] Search for other: Achondrites, Ungrouped achondrites | ||||||||||||||||||||||||||||||
| Comments: | Approved 8 Jun 2021 | ||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 110:
Northwest Africa 13955 (NWA 13955) Algeria Find: 2020 Classification: Ungrouped achondrite History: A single 1760 g stone was recovered by a group of Saharawi meteorite hunters in the Algerian part of the Erg Chech region during the summer of 2020, and then purchased by Ali Salamu from a dealer in Nouadhibou, Mauritania. Physical characteristics: The interior of the specimen has an overall light brown color with small orange patches, and contains sporadic smooth-walled vesicles. Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Cumulate texture. Composed of subhedral grains of olivine (~20 vol.%) and low-Ca pyroxene (~70 vol.%, zoned from small orthopyroxene cores to thick mantles of pigeonite) together with intercumulus calcic plagioclase (<10 vol.%) and accessory chromite (low-Ti to Ti-free), metal with (Fe/Ni ratios intermediate between those for typical typical kamacite and taenite), and Fe oxide (possibly representing altered sulfide). Sporadic vesicles or vugs are present. Geochemistry: Olivine (Fa33.8-34.8, FeO/MnO = 41-44, N = 4), orthopyroxene cores (Fs19.1-20.5Wo0.7-0.8, FeO/MnO = 29-30, N = 2), low-Ca pyroxene (Fs26.8-27.6Wo3.4-5.2, FeO/MnO = 26-28, N = 3), pigeonite (Fs25.1-26.7Wo7.7-7.8, FeO/MnO = 28-29, N = 2), plagioclase (An79.9-86.3Or1.1-0.5, N = 3). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 1.716, 1.777, 1.725; δ18O 3.828, 3.873, 3.782; Δ17O -0.305, -0.268, -0.272 (all data linearized). Classification: Ungrouped achondrite (ultramafic, vesicular). The meteorite is different from diogenites with orthopyroxene present as cores only, and predominance of pigeonite. The oxygen isotopic composition plots below the values for diogenites and typical eucrites. Specimens: 20.7 g including one polished thin section at UWB; remainder with Mr. A. Salamu. | ||||||||||||||||||||||||||||||
| Data from: MB110 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||||||
| Institutions and collections |
UNM: Institute of Meteoritics
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015) UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012) WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011) UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012) |
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| References: | Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4
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| Photos: |
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Geography:
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Statistics: This is 1 of 1270 approved meteorites from Algeria (plus 29 unapproved names) (plus 4 impact craters) | ||||||||||||||||||||||||||||||