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Northwest Africa 6864
Basic information Name: Northwest Africa 6864
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6864
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass:help 2.06 kg
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  L3.15
Recommended:  L3.15    [explanation]

This is 1 of 6 approved meteorites classified as L3.15.   [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 6 Sep 2013
Writeuphelp
Writeup from MB 102:

Northwest Africa 6864 (NWA 6864)

Northwest Africa

Purchased: 2011 Apr

Classification: Ordinary chondrite (L3.15)

Petrography: (A. Irving and S. Kuehner, UWS) Medium sized (some to 0.8 mm), closely packed and well-formed chondrules. Minerals are olivine, orthopyroxene, pigeonite, subcalcic augite, sodic plagioclase, chromite, altered kamacite, and troilite.

Geochemistry: Olivine (Fa0.5-45.8; Cr2O3 in ferroan olivine grains ranges from 0.12-0.45 wt.%, mean 0.28 wt.%, s.d. 0.09 wt.%, N = 15), orthopyroxene (Fs2.3-33.6Wo0.5-3.4), pigeonite (Fs18.1Wo17.6), subcalcic augite (Fs28.4Wo26.3). Oxygen isotopes (R. Tanaka, OkaU): analyses of acid-washed subsamples by laser fluorination gave δ18O 5.671, 6.062; δ17O 3.649, 4.024; Δ17O 0.662, 0.830 per mil.

Classification: Ordinary chondrite (L3.15). Subtype estimated to be 3.15 based on Cr2O3 range in ferroan olivine. Estimation of subtype based on chart (Fig. 15a) in Grossman and Brearley (2005). L designation consistent with chondrule size, and O isotopes.

Bibliography:
  • Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)
Data from:
  MB102
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2011 Apr
Mass (g):2061
Pieces:6
Class:L3.15
Shock stage:S2
Weathering grade:W2
Fayalite (mol%):0.5-45.8, n=17
Ferrosilite (mol%):2.3-33.6
Wollastonite (mol%):0.5-3.4
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):21.7
Type spec location:UWB
Main mass:S. Ralew
Comments:SR11-3; 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)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
OkaU: Institute for Study of the Earth's Interior, Okayama University, Misasa Tottori 682-0193, Japan (institutional address)
Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
John Lutzon   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6968 approved meteorites from (Northwest Africa) (plus 2012 unapproved names)

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