Meteoritical Bulletin: Entry for Northwest Africa 4929

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Northwest Africa 4929

Basic information

Name: Northwest Africa 4929
This is an OFFICIAL meteorite name.
Abbreviation: NWA 4929
Observed fall: No
Year found: 2007
Country: Morocco
Mass: 1214 g

Classification
history:

Meteoritical Bulletin:	MB 108	(2020)	Brachinite
Recommended:			Brachinite [explanation]

This is 1 of 55 approved meteorites classified as Brachinite. [show all]
Search for other: Brachinites, Primitive achondrites

Comments:

Approved 18 Aug 2019

Writeup

help

Writeup from MB 108:

Northwest Africa 4929 (NWA 4929)

Morocco

Find: 2007

Classification: Primitive achondrite (Brachinite)

History: Two pieces purchased in July and a third one in September 2007 in Erfoud, Morocco.

Physical characteristics: One complete stone broken into three pieces that fit together (weathered fracture), for a total weight of 1214 g (263+371+580). Partly covered with a slightly weathered, dark-brown fusion crust.

Petrography: A. Jambon, O. Boudouma and D. Badia; (UPVI) Mineral mode (from BSE imaging) Olivine 88% orthopyroxene 6.5%, augite 1%, chromite 2.3% and plagioclase 1.7%. Accessories include weathered kamacite and Ni rich metal. Typical polygonal granular texture; grain size 0.2-0.4 mm.

Geochemistry: Olivine Fa_33±1, FeO/MnO = 66 (n=24). Orthopyroxene En₇₀Fs₂₇Wo₂FeO/MnO = 41, augite En₄₆Fs₁₁Wo₄₄FeO/MnO = 28, chromite Cr/(Cr+Al) = 0.79, Mg/(Mg+Fe)=0.22 and TiO₂ = 1.05 wt%. Plagioclase An_30.Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of two acid-washed 1.5 mg aliquots of a powdered 70 mg bulk sample is δ¹⁷O=2.49‰, δ¹⁸O=5.33‰, Δ¹⁷O=-0.30‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively).

Classification: Achondrite (Brachinite)

Specimens: A total of 20.2 g of sample and one polished section is on deposit at UPVI. Moroccan Import Asnières, France holds the main mass.

Data from:
  MB108
  Table 0
  Line 0:

Place of purchase:	Erfoud
Date:	2007
Mass (g):	1214
Pieces:	3
Class:	Brachinite
Weathering grade:	signific
Fayalite (mol%):	33±1 (n=24)
Ferrosilite (mol%):	27±1 (n=30)
Wollastonite (mol%):	2.3±0.1 (n=30)
Classifier:	A. Jambon, O. Boudouma, D. Badia (UPVI); J. Gattacecca, C. Sonzogni (CEREGE)
Type spec mass (g):	20.2
Type spec location:	UPVI
Main mass:	Moroccan Import, Asnières, France
Comments:	Submitted by Albert Jambon

Plots:

O isotopes:

Institutions
and collections

CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de l'Arbois 13545 Aix-en-Provence Cedex 4 France, France (institutional address; updated 29 Oct 2018)
UPVI: Université Pierre et Marie Curie (Paris VI),Case 110, 4 Place Jussieu, 75005 Paris, France (institutional address; updated 5 Oct 2014)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150

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

Photos:

Credit	Photos
Public domain photographs:
Albert Jambon

Geography:

Morocco

Morocco

Coordinates:

Unknown.

Statistics:
This is 1 of 1973 approved meteorites from Morocco (plus 37 unapproved names) (plus 1 impact crater)

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