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Northwest Africa 13939
Basic information Name: Northwest Africa 13939
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13939
Observed fall: No
Year found: 2010
Country: (Northwest Africa)
Mass:help 57 g
Classification
  history:
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 260 approved meteorites (plus 1 unapproved name) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 29 May 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13939 (NWA 13939)

(Northwest Africa)

Purchased: 2010 Jun

Classification: Martian meteorite (Shergottite)

History: Purchased from a Moroccan mineral dealer at the meteorite show in Ensisheim, France

Physical characteristics: Fragment without fusion crust.

Petrography: (K. Metzler, IfP). Ultramafic igneous rock, mainly consisting of various pyroxenes, olivine, and some plagioclase. It exhibits a cumulate texture with grain sizes in the mm range with pyroxene-rich domains up to ~8 mm. Point counting on BSE images (n=175; area 1.6 cm2) revealed 46 vol% olivine, 47 vol% pyroxenes with various compositions, and 7 vol% plagioclase. Three different pyroxene varieties were found. Olivine partially shows brownish staining in transmitted light. It occurs in paragenesis with pyroxene and plagioclase and as poikilitically enclosed grains in the pyroxene-rich domains. Plagioclase is completely transformed to maskelynite by shock metamorphism. Vesicular shock melt pockets and veins are present, showing quench textures. Accessories are Mg-bearing ilmenite, two different varieties of chromium spinel, merrillite, and small amounts of pyrrhotite with tiny pentlandite inclusions.

Geochemistry: Mineral compositions and geochemistry: Olivine: Fa34.1±1.6 (Fa29.5-36.4); mean Fe/Mn (at.): 49.9; n=16. Pyroxene #1: Fs20.1±0.8 Wo2.9±0.3 (Fs19.0-21.0 Wo2.5-3.1); mean Fe/Mn (at.): 29.8; n=4. Pyroxene #2: Fs26.8±3.4 Wo9.4±1.5 (Fs21.9-30.8 Wo6.7-11.7); mean Fe/Mn (at.): 28.9; n=17. Pyroxene #3: Fs16.9±0.6 Wo32.3±1.7 (Fs16.0-18.0 Wo30.5-36.0); mean Fe/Mn (at.): 24.3; n=12. Plagioclase (maskelynite) An51.6±2.1 Or1.3±0.4 (An48.4-54.7 Or0.5-1.9); n=14. Chromium spinel #1: Atomic Cr/(Cr+Al)=0.87-0.89; Mg/(Mg+Fe)=0.25-0.34; TiO2=0.9-1.0 wt%; n=5. Chromium spinel #2: Atomic Cr/(Cr+Al)=0.79-0.82; Mg/(Mg+Fe)=0.10-0.16; TiO2=11.7-16.1 wt%; n=5.

Classification: Achondrite (martian, ultramafic shergottite)

Data from:
  MB110
  Table 0
  Line 0:
Place of purchase:Ensisheim, France
Date:P 2010 Jun
Mass (g):57
Pieces:1
Class:Martian (shergottite)
Shock stage:U-S5
Weathering grade:low
Fayalite (mol%):34.1
Ferrosilite (mol%):20.1; 26.8; 16.9
Wollastonite (mol%):2.9; 9.4; 32.3
Classifier:K. Metzler, IfP
Type spec mass (g):11.6
Type spec location:IfP
Main mass:anonymous
Comments:Submitted by K. Metzler, IfP
Institutions
   and collections
IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 110, in preparation (2021)
Find references in NASA ADS:
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Photos:
CreditPhotos
Public domain photographs:
Knut Metzler      
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7885 approved meteorites from (Northwest Africa) (plus 1958 unapproved names)

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