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Northwest Africa 8258
Basic information Name: Northwest Africa 8258
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8258
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 2.2 kg
Meteoritical Bulletin:  MB 104  (2015)  L3
Recommended:  L3    [explanation]

This is 1 of 851 approved meteorites (plus 2 unapproved names) classified as L3.   [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 22 Oct 2015
Writeup from MB 104:

Northwest Africa 8258 (NWA 8258)

Northwest Africa

Purchased: 2013 Dec

Classification: Ordinary chondrite (L3)

History: Purchased by Darryl Pitt in December 2013 from a dealer in Erfoud, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Unequilibrated chondrite consisting of fairly closely-packed, round to ellipsoidal chondrules (apparent diameter 1.3 ± 0.9 mm, many rimmed by sulfide, some glass-bearing) in a sparse, black, very fine-grained matrix composed of indeterminate silicates, pentlandite, troilite, rare taenite and goethite. No kamacite was found. An unusual 2.7 cm round object (not a CAI) is an equigranular aggregate of monticellite, Al-Fe-Cr-Mg spinel, olivine, anorthite and troilite surrounded by a rim of more magnesian olivine.

Geochemistry: Olivine (Fa1.3-46.3; Cr2O3 in ferroan examples is 0.10-0.22 wt.%, mean 0.16±0.05 wt.%, N = 7), orthopyroxene (Fs2.0-23.8Wo0.4-1.5, N = 3), pigeonite (Fs18.7Wo16.7), subcalcic augite (Fs20.4Wo37.6), monticellite in inclusion (Fa28.9Ln7.4). Oxygen isotopes (K. Ziegler, UNM): analyses of three acid-washed subsamples by laser fluorination gave, respectively, δ17O 3.339, 4.005, 3.635; δ18O 5.098, 5.582, 5.465; Δ17O 0.647, 1.058, 0.749 per mil.

Classification: Ordinary chondrite (L3, anomalous).

Specimens: 24 g including one polished thin section at UWB; the remainder is held by DPitt.

Data from:
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2013 Dec
Mass (g):2200
Shock stage:S2
Weathering grade:W1/2
Fayalite (mol%):1.3-46.3
Ferrosilite (mol%):2.0-23.8
Wollastonite (mol%):0.4-1.5
Magnetic suscept.:4.82
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):24
Type spec location:UWB
Main mass:D. Pitt
Comments:DP14-2; 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. 104, MAPS 52, 2284, Octover 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12930/full
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     This is 1 of 9746 approved meteorites from (Northwest Africa) (plus 1855 unapproved names)

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