Meteoritical Bulletin: Entry for Northwest Africa 6921

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Northwest Africa 6921

Basic information

Name: Northwest Africa 6921
This is an OFFICIAL meteorite name.
Abbreviation: NWA 6921
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass: 1749 g

Classification
history:

Meteoritical Bulletin:	MB 102	(2013)	CR6
Recommended:			CR6 [explanation]

This is 1 of 3 approved meteorites classified as CR6. [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated), and CR chondrites

Comments:

Approved 27 Sep 2013

Writeup

help

Writeup from MB 102:

Northwest Africa 6921 (NWA 6921)

Northwest Africa

Purchased: 2011 Aug

Classification: CR6

History: Purchased by Adam Aaronson in Temara, Morocco in 2011 August.

Physical characteristics: A single fresh, pale greenish stone (1749 g) with patchy black fusion crust.

Petrography: (A. Irving and S. Kuehner, UWS) Predominantly poikiloblastic texture, but with rare small BO chondrules. There are some larger olivine grains, but most of the specimen is an aggregate of finer olivine, orthopyroxene, minor clinopyroxene, intermediate plagioclase, fresh kamacite, chromite, troilite, and merrillite.

Geochemistry: Olivine (Fa_37.5-37.9, FeO/MnO = 91), orthopyroxene (Fs_29.5-29.7Wo_2.9-3.3, FeO/MnO = 54-57), clinopyroxene (Fs_11.5-12.7Wo_44.5-43.8, FeO/MnO = 31-34). Oxygen isotopes (R. Tanaka, OkaU): analyses of acid-washed subsamples by laser fluorination gave δ¹⁷O = -0.280, -0.065; δ¹⁸O = 2.788, 3.181; and Δ¹⁷O = -1.747, -1.738 per mil.

Classification: Carbonaceous chondrite (CR6). This specimen is a highly equilibrated CR chondrite paired with NWA 2994, NWA 3250, NWA 6901 and NWA 7317.

Specimens: A total of 20.3 g of sample and one polished thin section are on deposit at UWB. Aaronson holds the main mass.

Data from:
  MB102
  Table 0
  Line 0:

Place of purchase:	Temara
Date:	P 2011 Aug
Mass (g):	1749
Pieces:	1
Class:	CR6
Shock stage:	S2
Weathering grade:	W0
Fayalite (mol%):	37.5-37.9
Ferrosilite (mol%):	29.5-29.7; 11.5-12.7
Wollastonite (mol%):	2.9-3.3; 44.5-43.8
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	20.3
Type spec location:	UWB
Main mass:	A. Aaronson
Comments:	M1150; 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)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
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. 102, MAPS 50, 1662, September 2015

Find references in NASA ADS:
Find references in Google Scholar:

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9116 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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