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Northwest Africa 7957
Basic information Name: Northwest Africa 7957
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7957
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 86.1 g
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  CO3
Recommended:  CO3    [explanation]

This is 1 of 554 approved meteorites (plus 1 unapproved name) classified as CO3.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites
Comments: Approved 18 Nov 2013
Writeuphelp
Writeup from MB 102:

Northwest Africa 7957 (NWA 7957)

(Northwest Africa)

Purchased: 2013 Apr

Classification: Carbonaceous chondrite (CO3)

History: Purchased by Steve Witt from a Moroccan dealer in April 2013.

Petrography: (A. Irving and S. Kuehner, UWS) Small (0.2-0.6 mm), well-formed chondrules plus sparse mineral fragments and fine grained CAI (some containing hibonite) in a brown matrix.

Geochemistry: Olivine (Fa1.2-47.4; Cr2O3 in ferroan examples is 0.09-0.14 wt.%, mean 0.12 wt.%, s.d. 0.02 wt.%, N = 7), orthopyroxene (Fs1.4-6.7Wo3.5-3.3), subcalcic augite (Fs1.1-1.4Wo37.7-28.9).

Classification: Carbonaceous chondrite (CO3). Subtype is estimed to be 3.5 on the basis of the narrow distribution of Cr2O3 in ferroan olivine.

Specimens: 19.7 g and one polished thin section are at UWB. The remainder is held by Mr. S. Witt.

Data from:
  MB102
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2013 Apr
Mass (g):86.1
Pieces:1
Class:CO3
Shock stage:S2
Weathering grade:W2
Fayalite (mol%):1.2-47.4 (n=9)
Ferrosilite (mol%):1.4-6.7
Wollastonite (mol%):3.5-3.3
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):19.7
Type spec location:UWB
Main mass:S. Witt
Comments:SW13-4; submitted by A. Irving
Institutions
   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)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
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Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Suzanne De Paula   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7374 approved meteorites from (Northwest Africa) (plus 1957 unapproved names)

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