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Northwest Africa 12224
Basic information Name: Northwest Africa 12224
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12224
Observed fall: No
Year found: 2006
Country: (Northwest Africa)
Mass:help 230 g
Meteoritical Bulletin:  MB 107  (2018)  Howardite
Recommended:  Howardite    [explanation]

This is 1 of 421 approved meteorites classified as Howardite.   [show all]
Search for other: Achondrites, HED achondrites, and Howardites
Comments: Approved 13 Nov 2018
Writeup from MB 107:

Northwest Africa 12224 (NWA 12224)

(Northwest Africa)

Purchased: 2006 Jun

Classification: HED achondrite (Howardite)

History: Purchased from a Moroccan dealer at the mineral show in Sainte-Marie-aux-Mines, France

Petrography: (K. Metzler, IfP) Shock-compacted fine-grained breccia of dark gray appearance, criss-crossed by black shock melt veins up to several mm in width. It consists of gabbroic and basaltic (ophitic to subophitic) rock fragments and related debris. The majority of pyroxenes is free of exsolution lamellae, but exsolved pyroxenes also occur. Three grains of Fe-rich olivine have been found. This breccia contains devitrified melt droplets as well as clast-rich and clast-poor impact melt rocks. About 10-15% diogenitic components. Accessories are ilmenite, chromium spinel, troilite, silica polymorph, and Ni-poor metal (mostly oxidized).

Geochemistry: Mineral compositions and geochemistry: Low-Ca pyroxene (n=19): Fs35.1±5.1Wo5.4±0.7 (Fs29.3-49.7Wo4.1-7.1); mean Fe/Mn (at.): 33. Ca-rich pyroxene (n=5) Fs49.3±2.8Wo16.8±3.6 (Fs45.4-53.0Wo13.1-20.5); mean Fe/Mn (at.): 31. Diogenitic pyroxene (n=3) Fs24.1Wo1.9 (Fs21.8-26.0Wo1.6-2.1) mean Fe/Mn (at.): 32. Olivine (n=3) Fa77.7 (Fa76.5-78.6); mean Fe/Mn (at.): 47. Plagioclase (n=9): An83.8±3.9 (An78.9-92.0).

Data from:
  Table 0
  Line 0:
Place of purchase:Sainte-Marie-aux-Mines, France
Date:P 2006 Jun
Mass (g):230
Shock stage:strong
Weathering grade:moderate
Fayalite (mol%):77.7
Ferrosilite (mol%):24.1; 35.1; 49.3
Wollastonite (mol%):1.9; 5.4; 16.8
Classifier:K. Metzler, IfP
Type spec mass (g):20
Type spec location:IfP, Münster
Main mass:Anonymous
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 8559 approved meteorites from (Northwest Africa) (plus 1896 unapproved names)

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