Meteoritical Bulletin: Entry for Northwest Africa 7940

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Northwest Africa 7940

Basic information

Name: Northwest Africa 7940
This is an OFFICIAL meteorite name.
Abbreviation: NWA 7940
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass: 184 g

Classification
history:

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

This is 1 of 848 approved meteorites (plus 2 unapproved names) classified as L3. [show all]
Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)

Comments:

Approved 30 Dec 2013

Writeup

Writeup from MB 102:

Northwest Africa 7940 (NWA 7940)

(Northwest Africa)

Purchased: 2013 Feb

Classification: Ordinary chondrite (L3)

History: Purchased by Gary Fujihara in February 2013 from a Moroccan dealer at the Tucson Gem and Mineral Show.

Petrography: (A. Irving and S. Kuehner, UWS) Well-formed, closely-packed, medium-sized (0.4-2.2 mm) chondrules. Olivine, orthopyroxene, subcalcic augite, augite, sodic plagioclase, chromite, stained kamacite and troilite.

Geochemistry: Olivine (Fa_0.7-60.0; Cr₂O₃ in ferroan examples is 0.04-0.63 wt.%, mean 0.21±0.20 wt.%, N = 11), orthopyroxene (Fs_1.0-22.1Wo_0.7-0.4), subcalcic augite (Fs_3.4Wo_35.9), augite (Fs_10.4Wo_41.5).

Classification: Ordinary chondrite (L3.15). Estimation of subtype based Cr₂O₃ distribution in ferroan olivine per Fig. 15a of Grossman and Brearley (2005).

Specimens: 20.7 g and one polished thin section are at UWB. The remainder is held by Mr. G. Fujihara.

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:	Tucson
Date:	P 2013 Feb
Mass (g):	184
Pieces:	many
Class:	L3
Shock stage:	S2
Weathering grade:	W0/1
Fayalite (mol%):	0.7-60.0 (n = 13)
Ferrosilite (mol%):	1.0-22.1
Wollastonite (mol%):	0.7-0.4
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	20.7
Type spec location:	UWB
Main mass:	G. Fujihara
Comments:	GF13-3; 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, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023)

Catalogs:

References:

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

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Photos:

Credit	Photos
Photos uploaded by members of the Encyclopedia of Meteorites. (Caution, these are of unknown reliability)
Aeroliths Collection Theodossiou
Public domain photographs:
Gary Fujihara

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9710 approved meteorites from (Northwest Africa) (plus 1853 unapproved names)

Also see:

This lists the most popular meteorites among people who looked up this meteorite.

Revision
history:

This lists important revisions made to data for this record.

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