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Northwest Africa 12831
Basic information Name: Northwest Africa 12831
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12831
Observed fall: No
Year found: 2019
Country: Niger
Mass:help 150.8 g
Meteoritical Bulletin:  MB 108  (2020)  Lunar (feldsp. breccia)
Recommended:  Lunar (feldsp. breccia)    [explanation]

This is 1 of 312 approved meteorites classified as Lunar (feldsp. breccia).   [show all]
Search for other: Lunar meteorites
Comments: Approved 11 Oct 2019
Writeup from MB 108:

Northwest Africa 12831 (NWA 12831)


Purchased: 2019 May

Classification: Lunar meteorite (feldspathic breccia)

History: Purportedly found in Niger by nomads and purchased by Alexandre Debienne in May 2019 from a dealer in Agadir, Morocco.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Breccia composed of mineral clasts of high-Ca pyroxene (some exsolved), low-Ca pyroxene (some exsolved), anorthite and sparse olivine in a finer grained matrix containing silica polymorph, Cr- ilmenite, Ti-chromite, fayalite, hedenbergite, baddeleyite, troilite and merrillite.

Geochemistry: Olivine (Fa19.3-46.7, FeO/MnO = 85-93, N = 4), low-Ca pyroxene (Fs17.2Wo3.3; Fs26.2Wo4.7; FeO/MnO = 50-58; N = 2), pigeonite (Fs31.9Wo13.4, FeO/MnO = 56), augite (Fs14.4Wo36.4, FeO/MnO = 44; Fs5.9Wo47.2; FeO/MnO =34; N = 2), pigeonite exsolution lamella (Fs52.4Wo6.9, FeO/MnO = 68), augite exsolution lamella (Fs24.8Wo42.2, FeO/MnO = 61), anorthite (An96.9-97.0Or0.1, N = 2).

Classification: Lunar (feldspathic breccia).

Specimens: 20.02 g including a polished endcut at UWB; remainder with Mr. A. Debienne.

Data from:
  Table 0
  Line 0:
Place of purchase:Agadir
Date:P 2019 May
Mass (g):150.8
Class:Lunar (feldsp. breccia)
Shock stage:low
Weathering grade:low
Fayalite (mol%):19.3-46.7
Ferrosilite (mol%):17.2; 31.9; 14.4; 5.9
Wollastonite (mol%):3.3; 13.4; 36.4; 47.2
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):20.02
Type spec location:UWB
Main mass:A. Debienne
Comments:Work name AD19-1; submitted by A. Irving
   and collections
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)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     This is 1 of 106 approved meteorites from Niger (plus 4 unapproved names)

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