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Northwest Africa 12222
Basic information Name: Northwest Africa 12222
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12222
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 1.9 g
Meteoritical Bulletin:  MB 107  (2018)  Martian (polymict breccia)
Recommended:  Martian (polymict breccia)    [explanation]

This is 1 of 18 approved meteorites classified as Martian (polymict breccia).   [show all]
Search for other: Martian meteorites
Comments: Approved 12 Nov 2018
Revised 16 Nov 2018: Updated class; see NWA 7034)
Writeup from MB 107:

Northwest Africa 12222 (NWA 12222)

(Northwest Africa)

Purchased: 2018 Mar

Classification: Martian meteorite (polymict breccia)

Petrography: (K. Metzler, IfP) Achondritic breccia, consisting of lithic and mineral clasts, set in a fine-grained clastic matrix. The following minerals were identified: Plagioclase, pyroxene (occasionally with exsolution lamellae), Cl-bearing apatite, ilmenite, and pyrrhotite. Beside complex fine-grained lithologies two different basalt clasts were found.

Geochemistry: Mineral compositions and geochemistry: Basalt clast #1: Pyroxene (n=5) Fs37.6±0.2Wo35.7±0.4 (Fs37.3-37.8Wo35.2-36.1); mean Fe/Mn (at.)=36. Plagioclase (n=6): An55.2±3.5Or1.9±0.3 (An50.2-59.3Or1.3-2.2). Basalt clast #2: Pyroxene (n=7) Fs33.5±3.1 Wo4.0±0.9 (Fs25.6-34.6Wo1.6-4.6); mean Fe/Mn (at.)=38. Plagioclase (n=7): An53.5±4.2Or1.9±0.4 (An49.5-60.9Or1.4-2.7).

Classification: Martian (polymict breccia), based on texture and mineral composition. An values in Feldspar and Fe/Mn in pyroxene are typical of Martian basalts. This sample is most probably paired to NWA 7034 and pairings.

Data from:
  Table 0
  Line 0:
Place of purchase:Guelmim, Morocco
Date:P 2018 Mar
Mass (g):1.9
Class:Martian (polymict breccia)
Shock stage:moderate
Weathering grade:low
Ferrosilite (mol%):37.6, 33.5
Wollastonite (mol%):35.7, 4.0
Classifier:K. Metzler, IfP
Type spec mass (g):0.38
Type spec location:IfP
Main mass:Nourddine Azelmat, Morocco
Comments:Submitted by K. Metzler, IfP
   and collections
IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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     This is 1 of 8904 approved meteorites from (Northwest Africa) (plus 1871 unapproved names)

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