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Northwest Africa 12320
Basic information Name: Northwest Africa 12320
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12320
Observed fall: No
Year found: 2018
Country: Mauritania
Mass:help 4.46 kg
Meteoritical Bulletin:  MB 107  (2018)  Angrite
Recommended:  Angrite    [explanation]

This is 1 of 51 approved meteorites classified as Angrite.   [show all]
Search for other: Achondrites, Angrites
Comments: Approved 14 Dec 2018
Writeup from MB 107:

Northwest Africa 12320 (NWA 12320)


Purchased: 2018 Apr

Classification: Angrite

History: Two large, dark gray stones (2379 g and 1946 g) plus several smaller stones were found together at an unspecified site in Mauritania, and subsequently purchased by Darryl Pitt in April-July 2018 from a dealer in Nouakchott, Mauritania. An additional 14.2 g of the same material (confirmed by electron microprobe analyses) was purchased by Ben Hoefnagels in October 2018 from a Moroccan dealer.

Petrography: (A. Irving and S. Kuehner, UWS) Diabasic texture (grainsize 0.3-0.5 mm) with sparse vesicles containing partial interior coatings of secondary calcite and barite. Major minerals are zoned calcic olivine (with kirschsteinite rims), zoned Al-Ti-augite and anorthite (with slightly more sodic rims), together with accessory titanomagnetite, troilite and silicoapatite. Sparse xenocrysts of magnesian olivine with more ferroan reaction rims are present.

Geochemistry: Olivine (Fa39.6-79.7Ln1.7-14.8, FeO/MnO = 72-96, N = 5), clinopyroxene (Fs20.5-45.9Wo51.6-52.8, FeO/MnO = 68-143, TiO2 = 1.5-4.3 wt.%, Al2O3 = 6.9-7.8 wt.%, N = 4), kirschsteinite (Fa57.9-63.3Ln36.7-34.3, FeO/MnO = 68-75, N = 2), olivine xenocryst (core Fa13.8Ln0.6; rim Fa35.2Ln1.3; FeO/MnO = 85-103; N = 2), anorthite (core An99.7Ab0.2Or0.0; rim An96.6Ab3.3Or0.1; N = 2). Oxygen isotopes (K. Ziegler, UNM) Analyses of acid-washed subsamples by laser fluorination gave, respectively δ17O 2.268, 2.281, 2.339; δ18O 4.416, 4.407, 4.545; Δ17O -0.063, -0.046, -0.060 per mil.

Classification: Angrite (diabasic).

Specimens: 20.6 g including one polished thin section at UWB; remainder with DPitt, except for 14.2 g with Mr. B. Hoefnagels.

Data from:
  Table 0
  Line 0:
Place of purchase:Nouakchott, Mauritania
Date:P 2018 Apr
Mass (g):4459
Shock stage:low
Weathering grade:low
Fayalite (mol%):39.6-79.7
Ferrosilite (mol%):20.5-45.9
Wollastonite (mol%):51.6-52.8
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):20.6
Type spec location:UWB
Main mass:D. Pitt
Comments:Work name MVCH 338; submitted by A. Irving
Plots: O isotopes:  
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
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, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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Photos from the Encyclopedia of Meteorites:
Sergey Vasiliev   


     This is 1 of 222 approved meteorites from Mauritania (plus 2 unapproved names) (plus 2 impact craters)

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