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Northwest Africa 7556
Basic information Name: Northwest Africa 7556
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7556
Observed fall: No
Year found: 2010
Country: (Northwest Africa)
Mass:help 17.51 kg
Meteoritical Bulletin:  MB 104  (2015)  L4-6
Recommended:  L4-6    [explanation]

This is 1 of 57 approved meteorites (plus 1 unapproved name) classified as L4-6.   [show all]
Search for other: L chondrites, L chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 4 Sep 2015
Writeup from MB 104:

Northwest Africa 7556 (NWA 7556)

(Northwest Africa)

Purchased: 2010 Dec

Classification: Ordinary chondrite (L4-6)

History: Purchased by Dr. David Gregory in December 2010 from a Moroccan dealer.

Physical characteristics: A single, large brown stone (17.509 kg) lacking fusion crust.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia consisting of clasts and some discrete well-formed chondrules set in a sparse matrix. Some clasts have discernible chondrules whereas others have been almost completely recrystallized. All components are compositionally equilibrated.

Geochemistry: Olivine (Fa25.2-25.3, N = 3), orthopyroxene (Fs20.4-20.9Wo1.9-1.4, N = 3), augite (Fs8.9-9.9Wo42.0-42.4, N = 2). Oxygen isotopes (K. Ziegler, UNM): analyses of three acid-washed subsamples by laser fluorination gave, respectively, δ17O 3.882, 3.618, 4.101; δ18O 5.367, 5.043, 5.664; Δ17O 1.048, 0.955, 1.110 per mil.

Classification: Ordinary chondrite (L4-6 breccia).

Specimens: 76 g including one polished thin section at UWB; main mass with DGregory.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2010 Dec
Mass (g):17509
Shock stage:S2
Weathering grade:W1
Fayalite (mol%):25.2-25.3
Ferrosilite (mol%):20.4-20.9
Wollastonite (mol%):1.9-1.4
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):76
Type spec location:UWB
Main mass:DGregory
Comments:Submitted by A. Irving
Data from:
  Table 0
  Line 0:
Type spec location:27.3 g at UWB; remainder with owner.
Comments:Work name 1478
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)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 104, MAPS 52, 2284, Octover 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12930/full
Published in Meteoritical Bulletin, no. 113, in preparation (2024)
Find references in NASA ADS:
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     This is 1 of 9806 approved meteorites from (Northwest Africa) (plus 1855 unapproved names)

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