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Northwest Africa 13031
Basic information Name: Northwest Africa 13031
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13031
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 211 g
Classification
  history:
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 213 approved meteorites (plus 1 unapproved name) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 9 Feb 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13031 (NWA 13031)

(Northwest Africa)

Purchased: 2018 Mar

Classification: Martian meteorite (Shergottite)

History: A group of four stones were found together at an unspecified location and purchased in Agadir, Morocco, by Aziz Habibi in March 2019.

Physical characteristics: The four stones (total weight 211 g) all have a distinctive light-green color. Fresh interiors exhibit sparse larger, lighter-colored macrocrysts in a predominant darker, finer-grained groundmass.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Composed predominantly of a relatively fine grained assemblage (mean grainsize 0.3 mm) of polysynthetically-twinned, prismatic clinopyroxene and maskelynite with accessory Ti-free chromite, Ti-chromite, ilmenite, ulvöspinel, pyrrhotite, merrillite and silica polymorph. Very sparse macrocrysts (up to 2 mm) of orthopyroxene and pigeonite (with included olivine) are present, as well as rare very thin secondary calcite veinlets.

Geochemistry: Orthopyroxene macrocryst core (Fs20.5Wo3.2, FeO/MnO = 30), pigeonite cores (Fs24.7-28.6Wo8.5-10.4, FeO/MnO = 29-31, N = 2), high-Ca pyroxene rims (Fs47.3-58.7Wo14.1-19.3, FeO/MnO = 36-39, N = 3), olivine in pigeonite macrocryst (Fa34.5-35.8, FeO/MnO = 50-56, N = 4), maskelynite (An58.9-59.5Or0.5-0.3, N = 2).

Classification: Shergottite (aphyric, pigeonite-rich with sparse macrocrysts).

Specimens: 20.1 g including one polished thin section at UWB; remainder with A. Habibi.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Agadir
Date:P 2018 Mar
Mass (g):211
Pieces:4
Class:Martian (shergottite)
Shock stage:high
Weathering grade:low
Fayalite (mol%):34.5-35.8
Ferrosilite (mol%):20.5; 24.7-28.6; 47.3-58.7
Wollastonite (mol%):3.2; 8.5-10.4; 14.1-19.3
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):20.1
Type spec location:UWB
Main mass:A. Habibi
Comments:Work name AH 720; 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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7228 approved meteorites from (Northwest Africa) (plus 1998 unapproved names)

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