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Northwest Africa 12418
Basic information Name: Northwest Africa 12418
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12418
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 31.8 g
Meteoritical Bulletin:  MB 108  (2020)  Martian (shergottite)
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 298 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 9 Feb 2019
Writeup from MB 108:

Northwest Africa 12418 (NWA 12418)

(Northwest Africa)

Purchased: 2018 Dec

Classification: Martian meteorite (Shergottite)

History: Purchased by Ben Hoefnagels in December 2018 from a dealer in Zagora, Morocco.

Physical characteristics: A small (31.8 g) completely crusted stone. The fresh interior is light green in color with some visible glassy maskelynite.

Petrography: (A. Irving and S. Kuehner, UWS) Poikilitic texture. Composed predominantly of olivine and clinopyroxene (both exhibiting limited compositional zoning in Fe and Mg) with subordinate maskelynite and accessory ilmenite, Ti-chromite, Mg-merrillite and pyrrhotite. Minor cross-cutting veinlets of secondary calcite are present.

Geochemistry: Olivine (core Fa 33.9, FeO/MnO = 52; rim Fa41.5, FeO/MnO = 50), pigeonite (Fs26.0-26.1Wo5.0-5.1; Fs32.5-37.4Wo14.5-9.7; FeO/MnO = 29-33; N = 5), subcalcic augite (Fs21.4-21.6Wo29.6-30.3, FeO/MnO = 28-29, N = 2), maskelynite (An51.8-53.8Or1.4-1.5, N = 2).

Classification: Martian (shergottite, poikilitic)

Specimens: 6.4 g including one polished thin section at UWB; remainder with Mr. B. Hoefnagels.

Data from:
  Table 0
  Line 0:
Place of purchase:Zagora
Date:P 2018 Dec
Mass (g):31.8
Class:Martian (shergottite)
Shock stage:high
Weathering grade:low
Fayalite (mol%):33.9-41.5
Ferrosilite (mol%):26.0-26.1; 32.5-37.4; 21.4-21.6
Wollastonite (mol%):5.0-5.1; 14.5-9.7; 29.6-30.3
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):6.4
Type spec location:UWB
Main mass:B. Hoefnagels
Comments:Work name BH166; 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)
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 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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