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Northwest Africa 13431
Basic information Name: Northwest Africa 13431
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13431
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 308 g
Recommended:  H4    [explanation]

This is 1 of 6313 approved meteorites (plus 2 unapproved names) classified as H4.   [show all]
Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 19 Sep 2020
Writeup from MB 109:

Northwest Africa 13431 (NWA 13431)

(Northwest Africa)

Purchased: 2019 Mar

Classification: Ordinary chondrite (H4)

History: Purchased by John Divelbiss in March 2019 from Sean Tutorow, who had acquired the specimen from a Moroccan dealer.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Well-formed chondrules are set in a relatively coarse grained, recrystallized matrix containing kamacite (altered), taenite, troilite, sodic plagioclase, low-Ti chromite, merrillite and chlorapatite.

Geochemistry: Olivine (Fa18.5±0.1, range Fa18.4-18.6, N = 4), low-Ca pyroxene (Fs15.9±0.7Wo1.0±0.7, range Fs14.9-16.3Wo0.3-1.6, N = 4), augite (Fs7.2Wo34.1; Fs5.9Wo45.7; N = 2).

Classification: Ordinary chondrite (H4).

Specimens: 32.5 g including one polished thin section at UWB; remainder with Mr. J. Divelbiss.

Data from:
  Table 0
  Line 0:
Place of purchase:Greeley, CO
Date:P 2019 Mar
Mass (g):308
Shock stage:S2
Weathering grade:W2
Fayalite (mol%):18.5±0.1
Ferrosilite (mol%):15.9±0.7
Wollastonite (mol%):1.0±0.7
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):32.5
Type spec location:UWB
Main mass:J. Divelbiss
Comments:Work name JD20-3; 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)
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)
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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     This is 1 of 8138 approved meteorites from (Northwest Africa) (plus 1941 unapproved names)

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