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Northwest Africa 12838
Basic information Name: Northwest Africa 12838
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12838
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 58.3 g
Meteoritical Bulletin:  MB 108  (2020)  Eucrite-mmict
Recommended:  Eucrite-mmict    [explanation]

This is 1 of 269 approved meteorites classified as Eucrite-mmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 11 Oct 2019
Writeup from MB 108:

Northwest Africa 12838 (NWA 12838)

(Northwest Africa)

Purchased: 2018

Classification: HED achondrite (Eucrite, monomict)

History: Purchased by Mbark Arjdal from an Algerian dealer in 2018.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Breccia consisting of closely-packed eucrite clasts (exhibiting partly recrystallized subophitic texture) plus sparse related crystalline debris. Minerals are exsolved pigeonite, calcic plagioclase, silica polymorph, ilmenite, Ti chromite, troilite, rare zircon and minor secondary calcite.

Geochemistry: Orthopyroxene (Fs59.9-60.2Wo3.7-3.0, FeO/MnO = 33-34, N = 2), clinopyroxene (Fs28.8-31.9Wo42.1-38.5, FeO/MnO = 31-32, N = 2), plagioclase (An83.6-84.2Or0.6, N = 2).

Classification: Eucrite (monomict breccia).

Specimens: 12.6 g including one polished thin section at UWB; remainder with Mr. M. Arjdal.

Data from:
  Table 0
  Line 0:
Place of purchase:Algeria
Date:P 2018
Mass (g):58.3
Shock stage:low
Weathering grade:low
Ferrosilite (mol%):59.9-60.2
Wollastonite (mol%):3.7-3.0
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):12.6
Type spec location:UWB
Main mass:M. Arjdal
Comments:Work name Arj M4; 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 8745 approved meteorites from (Northwest Africa) (plus 1880 unapproved names)

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