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Northwest Africa 6474
Basic information Name: Northwest Africa 6474
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6474
Observed fall: No
Year found: 2010
Country: (Northwest Africa)
Mass:help 312 g
Classification
  history:
Meteoritical Bulletin:  MB 100  (2012)  Brachinite
Recommended:  Brachinite    [explanation]

This is 1 of 45 approved meteorites classified as Brachinite.   [show all]
Search for other: Brachinites, Primitive achondrites
Comments: Approved 31 Jan 2012
Writeuphelp
Writeup from MB 100:

Northwest Africa 6474 (NWA 6474)

(Northwest Africa)

Purchased: Sept 2010

Classification: Primitive achondrite (Brachinite)

History: Purchased in 2010 September by Marc Jost from a dealer in Smara, Western Sahara.

Physical characteristics: A single dark brown stone weighing 312 g.

Petrography: Protogranular aggregate of olivine, clinopyroxene, zincian chromite, troilite, chlorapatite, minor intermediate plagioclase and taenite.

Geochemistry: Olivine Fa35.7-36.1, Fe/Mn=71-76; clinopyroxene Fs9.8-10.0Wo45.4-46.0, Fe/Mn=33-35, Cr2O3=0.68-0.70 wt%. Oxygen isotopes (D. Rumble, CIW and R. Tanaka, OkaU): analyses of acid-washed subsamples by laser fluorination gave, respectively δ17O = 1.98, 1.943, 2.181; δ18O = 3.879, 3.829, 4.234; Δ17O = -0.064, -0.073, -0.048 per mil.

Classification: Achondrite (brachinite). This specimen has textural and mineralogical similarities to NWA 4882, but differs significantly in its oxygen isotopic composition.

Specimens: A total of 20.2 g and one polished thin section are on deposit at UWS. Mr. M. Jost holds the main mass.

Data from:
  MB100
  Table 1
  Line 1387:
Place of purchase:Smara
Date:P Sept 2010
Mass (g):312
Pieces:1
Class:Brachinite
Shock stage:low
Weathering grade:moderate
Fayalite (mol%):35.7-36.1
Ferrosilite (mol%):9.8-10.0
Wollastonite (mol%):45.4-46.0
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):20.2
Type spec location:UWS
Main mass:M. Jost
Comments:Submitted by A. Irving
Plots: O isotopes:  
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)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
OkaU: Institute for Study of the Earth's Interior, Okayama University, Misasa Tottori 682-0193, Japan (institutional address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 100, MAPS 49, E1-E101 (2014)
Find references in NASA ADS:
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Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Dominik Stoeckli   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6752 approved meteorites from (Northwest Africa) (plus 2052 unapproved names)

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