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Northwest Africa 2653
Basic information Name: Northwest Africa 2653
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2653
Observed fall: No
Year found: 2004
Country: Northwest Africa
Mass:help 51 g
Classification
  history:
Recommended:  CV7    [explanation]

This is 1 of 2 approved meteorites classified as CV7.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated) , CV chondrites, and CV chondrites (equilibrated)
Comments: Approved 27 Mar 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 2653 (NWA 2653)

Northwest Africa

Purchased: 2004

Classification: CV7

History: Acquired by Rob Wesel in 2004 as part of a parcel of specimens purchased from Moroccan dealers by a consortium of collectors.

Petrography: (A. Irving and S. Kuehner, UWS; T. Bunch and J. Wittke, NAU) Triple grain junction texture devoid of chondrules or chondrule remnants. Mostly composed of fine-grained (<0.5 mm, mean 0.185 mm) polygonal, subhedral grains with the exception of several larger (1.2-3.0 mm) orthopyroxene grains that contain very small (<0.1 mm) olivine inclusions. Minerals are compositionally homogeneous olivine, orthopyroxene, clinopyroxene and intermediate plagioclase (100 to 700 µm) with accessory merrillite, chlorapatite, chromite, troilite, altered kamacite and taenite. Secondary goethite (formed by terrestrial weathering) occurs as thin veinlets and thin coatings on grain boundaries.

Geochemistry: Olivine (Fa22.0-22.2, FeO/MnO = 65-83, N = 3), orthopyroxene (Fs19.1-19.6Wo2.7-2.2, FeO/MnO = 39-43, N = 3), clinopyroxene (Fs7.8-8.3Wo44.8-44.5, FeO/MnO = 29-43, N = 2), plagioclase (An53.2-53.4Or2.3-2.4, N = 2), chromite (Cr/(Cr+Al) = 84.5), taenite (Ni = 18.9 wt. %). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively δ17O -2.333, 1.162, -3.523; δ18O 2.673, 7.086, 1.227; Δ17O -3.744, -2.579, -4.171 per mil.

Classification: Carbonaceous chondrite (CV7). This highly recrystallized, chondrule-free material is paired with Northwest Africa 3133; oxygen isotopes for both specimens plot on the trend line for CV chondrites. The bulk elemental abundances, chromium isotopes and tungsten isotopes for NWA 3133 (and by inference for NWA 2653) overlap with corresponding values for Allende and other CV chondrites.

Specimens: 10.2 g including one polished thin section and a polished slice at PSF; the remaining material is with Mr. R. Wesel.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2004
Mass (g):51
Pieces:several
Class:CV7
Shock stage:low
Weathering grade:moderate
Fayalite (mol%):22.0-22.2
Ferrosilite (mol%):19.1-19.6
Wollastonite (mol%):2.7-2.2
Classifier:A. Irving and S. Kuehner, UWS; T. Bunch & J. Wittke, NAU
Type spec mass (g):10.2
Type spec location:PSF
Main mass:R. Wesel
Comments:Submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
PSF: Planetary Studies Foundation,10 Winterwood Lane, Unit B, Galena, Illinois 61036-9283, United States; Website (institutional address; updated 1 Dec 2011)
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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Tony Irving   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 3 approved meteorites from Northwest Africa (plus 3 unapproved names)

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