Meteoritical Bulletin: Entry for Northwest Africa 7646

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Northwest Africa 7646

Basic information

Name: Northwest Africa 7646
This is an OFFICIAL meteorite name.
Abbreviation: NWA 7646
Observed fall: No
Year found: 2012
Country: (Northwest Africa)
Mass: 402 g

Classification
history:

Meteoritical Bulletin:	MB 102	(2013)	L3
Recommended:			L3 [explanation]

This is 1 of 718 approved meteorites (plus 1 unapproved name) classified as L3. [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)

Comments:

Approved 27 Sep 2013

Writeup

help

Writeup from MB 102:

Northwest Africa 7646 (NWA 7646)

(Northwest Africa)

Purchased: 2012 Dec

Classification: Ordinary chondrite (L3)

History: Purchased by Darryl Pitt in December 2012 from a dealer in Erfoud, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Closely packed chondrules (0.2 to 2 mm) dominated by PO and PP. Minerals include olivine, orthopyroxene, subcalcic augite, augite, sodic plagioclase, chromite, troilite and altered kamacite.

Geochemistry: Olivine Fa_3.9-44.1, n=10; Cr₂O₃ in ferroan olivine 0.03-0.11 wt.%, mean 0.07 wt.%, sd 0.03 wt.%, N = 7. Orthopyroxene Fs_1.8-19.7Wo_0.9-1.9; subcalcic augite Fs_9.4Wo_32.4; augite Fs_11.6Wo_41.0.

Classification: Estimated L3.5. Chondrule size and range consistent with L. Subtype estimated to be 3.5 based on Cr₂O₃ range in ferroan olivine. Estimation of subtype based on histograms (Fig. 4) in Grossman and Brearley (2005).

Specimens: 24.6 g and one polished thin section at UWB. DPitt holds the main mass.

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 2012 Dec
Mass (g):	402
Pieces:	1
Class:	L3
Shock stage:	S2
Weathering grade:	W2
Fayalite (mol%):	3.9-44.1
Ferrosilite (mol%):	1.8-19.7
Wollastonite (mol%):	0.9-1.9
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	24.6
Type spec location:	UWB
Main mass:	DPitt
Comments:	D724; 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)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015

Find references in NASA ADS:
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Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 7655 approved meteorites from (Northwest Africa) (plus 1972 unapproved names)

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