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Northwest Africa 12442
Basic information Name: Northwest Africa 12442
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12442
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 164 g
Classification
  history:
Recommended:  Ureilite    [explanation]

This is 1 of 510 approved meteorites classified as Ureilite.   [show all]
Search for other: Achondrites, Ureilites
Comments: Approved 27 Jul 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12442 (NWA 12442)

(Northwest Africa)

Purchased: 2018 Apr

Classification: Ureilite

History: Puchased in Alnif, Morocc,o by Adam Aaronson in April 2018.

Petrography: (A. Irving and S. Kuehner, UWS) Protogranular aggregate composed almost entirely (>90 vol.%) of olivine (with reduced magnesian rims) plus minor pigeonite, graphite and secondary calcite. Irregular interstitial regions along grain boundaries are composed of Fe metal, magnesian pigeonite, subcalcic augite and Si-rich glass.

Geochemistry: Olivine (cores Fa21.8-21.9; rim Fa11.6; N = 3), pigeonite (Fs17.3Wo11.7), grain boundary pigeonite (Fs6.2-8.5Wo10.7-10.6; Fs5.4Wo22.4; N = 3), grain boundary subcalcic augite (Fs7.4Wo27.0), grain boundary siliceous glass (SiO2 68.9 wt.%, Al2O3 16.9 wt.%, CaO 5.7 wt.%, MgO 3.0 wt.%, FeO 1.0 wt.%, Na2O 1.3 wt.%).

Classification: Ureilite (dunitic). The grain boundary polyphase assemblages composed of Fe metal+clinopyroxene+siliceous glass are a unique feature of this specimen.

Specimens: 20.6 g including one polished thin section at UWB; remainder with Aaronson.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Alnif
Date:P 2018 Apr
Mass (g):164
Pieces:1
Class:Ureilite
Shock stage:low
Weathering grade:low
Fayalite (mol%):21.8-21.9
Ferrosilite (mol%):17.3
Wollastonite (mol%):11.7
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):20.3
Type spec location:UWB
Main mass:Aaronson
Comments:Work name M2142; 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)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
A. Irving   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6877 approved meteorites from (Northwest Africa) (plus 2037 unapproved names)

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