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Northwest Africa 8641
Basic information Name: Northwest Africa 8641
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8641
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 5.9 kg
Classification
  history:
Recommended:  Lunar (feldsp. breccia)    [explanation]

This is 1 of 121 approved meteorites classified as Lunar (feldsp. breccia).   [show all]
Search for other: Lunar meteorites
Comments: Approved 25 Nov 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 8641 (NWA 8641)

(Northwest Africa)

Purchased: 2014 May

Classification: Lunar meteorite (feldspathic breccia)

History: Purchased in May 2014 by Darryl Pitt from a dealer in Erfoud, Morocco.

Physical characteristics: A large (5895 g) rounded, ellipsoidal dark gray stone with white clasts visible and with a beige, clayey coating on one side.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia composed of light colored clasts in a darker matrix. Major minerals are olivine, orthopyroxene, pigeonite, augite and anorthite. Minor constituents include symplectitic intergrowths of fayalite+hedenbergite+silica polymorph, ilmenite, Ti-rich chromite, troilite, and rare exsolved pigeonite, kamacite and secondary barite.

Geochemistry: Olivine (Fa23.3-31.8; FeO/MnO = 94-97, N = 3), orthopyroxene (Fs29.7Wo3.1; FeO/MnO = 64), pigeonite (Fs24.1Wo6.4; FeO/MnO = 59), augite (Fs13.6-39.4Wo39.4-43.5; FeO/MnO = 44-45, N = 2), plagioclase (An94.6-99.7Or0.3-0.1, N = 3). Bulk composition (R. Korotev, WUSL) INAA of subsamples gave the following mean abundances (in wt.%) FeO 5.35, Na2O 0.48; (in ppm) Sc 12.3, Ni 140, Ba 320, La 6.4, Sm 2.9, Eu 1.05, Yb 2.0, Lu 0.287, Hf 2.1, Th 0.90.

Classification: Lunar (feldspathic regolithic breccia).

Specimens: 20.5 g including a polished endcut at UWB. The remainder is held by DPitt.

Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2014 May
Mass (g):5895
Pieces:1
Class:Lunar (feldsp. breccia)
Shock stage:low
Weathering grade:low
Fayalite (mol%):23.3-31.8
Ferrosilite (mol%):29.7; 24.1; 13.6-39.4
Wollastonite (mol%):3.1; 6.4; 39.4-43.5
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):20.5
Type spec location:UWB
Main mass:D. Pitt
Comments:MAC 41; submitted by A. Irving
Institutions
   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)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, in preparation (2014)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 5838 approved meteorites from (Northwest Africa) (plus 2066 unapproved names)

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