Meteoritical Bulletin: Entry for Northwest Africa 7633

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Northwest Africa 7633

Basic information

Name: Northwest Africa 7633
This is an OFFICIAL meteorite name.
Abbreviation: NWA 7633
Observed fall: No
Year found: 2012
Country: (Northwest Africa)
Mass: 36 g

Classification
history:

Meteoritical Bulletin:	MB 102	(2013)	CO3
Recommended:			CO3 [explanation]

This is 1 of 623 approved meteorites (plus 1 unapproved name) classified as CO3. [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites

Comments:

Approved 6 Sep 2013

Writeup

help

Writeup from MB 102:

Northwest Africa 7633 (NWA 7633)

(Northwest Africa)

Purchased: 2012

Classification: Carbonaceous chondrite (CO3)

History: Purchased by Ralew in 2012 from a dealer in Erfoud, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Fresh, matrix-rich unequilibrated chondrite composed of separated tiny chondrules and mineral fragments in a black, very fine grained matrix.

Geochemistry: Olivine (Fa_0.5-50.9; Cr₂O₃ in ferroan examples = 0.12-0.43 wt.%, mean 0.22, s.d. 0.10, N =9), orthopyroxene (Fs_0.9-1.0Wo_1.3-1.2), subcalcic augite (Fs_1.3-5.2Wo_33.0-28.5). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively δ¹⁷O = -8.130, -7.044; δ¹⁸O = -5.045, -3.978; Δ¹⁷O = -5.466, -4.944 per mil (for a TFL slope of 0.528). These values plot on an extension of the established trend for CV chondrites towards more oxygen 16-rich compositions, but below the trend for CO chondrites.

Classification: Carbonaceous chondrite (CO3.15). Estimated subtype based on Cr₂O₃ range in ferroan olivine based on Fig. 15 of Grossman and Brearley (2005).

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
Mass (g):	36
Pieces:	many
Class:	CO3
Shock stage:	S2
Weathering grade:	W0/1
Fayalite (mol%):	0.5-50.9
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	7.2
Type spec location:	UWB
Main mass:	S. Ralew
Comments:	Rudi-2; submitted by A. Irving

Plots:

O isotopes:

Institutions
and collections

UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
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)
Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private 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 9013 approved meteorites from (Northwest Africa) (plus 1869 unapproved names)

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