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Northwest Africa 12458
Basic information Name: Northwest Africa 12458
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12458
Observed fall: No
Year found: 2005
Country: (Northwest Africa)
Mass:help 249 g
Recommended:  L3-6    [explanation]

This is 1 of 61 approved meteorites classified as L3-6.   [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 2 Aug 2020
Writeup from MB 109:

Northwest Africa 12458 (NWA 12458)

(Northwest Africa)

Purchased: 2005

Classification: Ordinary chondrite (L3-6)

History: Purchased by an anonymous collector from a dealer at the Munich Show in 2005, subsequently acquired by the Hollis Collection and then donated to PSF.

Petrography: (A. Irving and S. Kuehner, UWS; P. Carpenter, WUSL) Breccia composed of well-formed chondrules (apparent diameter 810±410 µm, N = 20) plus some angular Type 5 and Type 6 clasts in a finer grained matrix containing stained metal, merrillite and chlorapatite.

Geochemistry: Olivine (Fa19.7±8.0, range Fa6.3-27.1, N = 7; Cr2O3 in ferroan examples 0.02-0.08 wt.%, mean 0.04±0.03 wt.%, N = 3), orthopyroxene (Fs12.9±8.7Wo0.9±1.1, range 3.4-20.5Wo0.3-2.1, N = 3), clinopyroxene (Fs4.1-9.4Wo36.7-43.2, N = 2), olivine in Type 6 lithic clast (Fa25.0±0.0, N = 2). Magnetic susceptibility log χ (× 10-9 m3/kg) = 4.67.

Classification: Ordinary chondrite (L3-6 breccia). Affinity to L chondrites is established from olivine composition in equilibrated lithic clasts and bulk magnetic susceptibility.

Specimens: The entire specimen including one polished thin section is at PSF.

Data from:
  Table 0
  Line 0:
Place of purchase:Munich
Date:P 2005
Mass (g):249
Shock stage:S2
Weathering grade:W1
Fayalite (mol%):19.7±8.0
Ferrosilite (mol%):12.9±8.7
Wollastonite (mol%):0.9±1.1
Classifier:A. Irving and S. Kuehner, UWS; P. Carpenter
Type spec mass (g):249
Type spec location:PSF
Main mass:PSF
Comments:Work name CHC18045; submitted by A. Irving
   and collections
PSF: Planetary Studies Foundation,10 Winterwood Lane, Unit B, Galena, Illinois 61036-9283, United States; Website (institutional address; updated 1 Dec 2011)
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)
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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     This is 1 of 8745 approved meteorites from (Northwest Africa) (plus 1880 unapproved names)

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