Meteoritical Bulletin: Entry for Northwest Africa 11239

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Northwest Africa 11239

Basic information

Name: Northwest Africa 11239
This is an OFFICIAL meteorite name.
Abbreviation: NWA 11239
Observed fall: No
Year found: 2016
Country: (Northwest Africa)
Mass: 314 g

Classification
history:

Meteoritical Bulletin:	MB 106	(2018)	Enst achon
Recommended:			Enst achon [explanation]

This is 1 of 11 approved meteorites classified as Enst achon. [show all]
Search for other: Achondrites, Enstatite achondrites, and Enstatite-rich meteorites

Comments:

Approved 16 May 2017

Writeup

help

Writeup from MB 106:

Northwest Africa 11239 (NWA 11239)

(Northwest Africa)

Purchased: 2016 Dec

Classification: Enstatite achondrite

History: Purchased by Roger Jones in December 2016 from a dealer in Guelmim, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Triple grain junction texture. The predominant mineral is enstatite with subordinate relatively sodic plagioclase (oligoclase-andesine) plus accessory Cr-troilite and Si-bearing kamacite. Minor terrestrial alteration has produced orange iron hydroxides distributed along grain boundaries.

Geochemistry: Enstatite (Fs_0.1Wo_0.3-0.5, N = 2), plagioclase (An_28.7-32.8Or_1.7-1.6, N = 2), metal (Si 1.5 wt.%, Ni 5.6-5.7 wt.%, Co 0.46 wt.%, N = 3).

Classification: Enstatite achondrite. This specimen differs from aubrites in having a metamorphic, triple grain junction texture, and it also lacks the typical sulfide minerals present in most aubrites. A careful search revealed only Cr-troilite in addition to Si-bearing kamacite as the obvious accessory phases; no daubreelite, alabandite or oldhamite were found.

Specimens: 20.5 g including one polished thin section and one polished mount at UWB; remainder with Mr. R. Jones.

Data from:
  MB106
  Table 0
  Line 0:

Place of purchase:	Guelmim
Date:	P 2016 Dec
Mass (g):	314
Pieces:	1
Class:	Enst achon
Shock stage:	low
Weathering grade:	low
Ferrosilite (mol%):	0.1
Wollastonite (mol%):	0.3-0.5
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	20.5
Type spec location:	UWB
Main mass:	R. Jones
Comments:	Work name RBJ16-6; 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)

Catalogs:

References:

Published in Gattacceca J., Bouvier A., Grossman J., Metzler K., and Uehara M. (2019) Meteoritical Bulletin, no. 106. Meteorit. Planet. Sci. 54 in press.

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Photos:

Credit	Photos
Public domain photographs:
A. Irving

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9128 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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