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Northwest Africa 7493
Basic information Name: Northwest Africa 7493
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7493
Observed fall: No
Year found: 2012
Country: Morocco
Mass:help 503 g
Classification
  history:
Meteoritical Bulletin:  MB 101  (2012)  Lunar (feldsp. breccia)
Recommended:  Lunar (feldsp. breccia)    [explanation]

This is 1 of 174 approved meteorites classified as Lunar (feldsp. breccia).   [show all]
Search for other: Lunar meteorites
Comments: Approved 12 Dec 2012
Writeuphelp
Writeup from MB 101:

Northwest Africa 7493 (NWA 7493)

Morocco

Purchased: August 2012

Classification: Lunar meteorite (feldspathic breccia)

History: Found in July 2011, reportedly near Zag, Morocco. Purchased by Jay Piatek and Matt Morgan in August 2012 from a dealer in Ouarzazate.

Physical characteristics: Six matching separate stones (total weight 503 g), consisting of two larger stones (341 g and 146 g) and four smaller pieces (total 16 g). Irregular, desert-weathered exterior with heavy patina in places and visible light and dark patches. Sawn slices exhibit a brecciated texture dominated by medium gray, tan and white lithic clasts plus white feldspar grains (up to 5 mm across) set in a sparse, darker gray matrix. Some thin veins of terrestrial weathering products visible.

Petrography: (C. Agee, UNM; A. Irving, UWS; R. Mills, JSC) Microprobe examination of five polished mounts and a complete slice shows this specimen to be a fragmental breccia composed primarily of quenched melt clasts and calcic plagioclase grains occurring in a wide range of grain sizes. There are numerous scattered olivine and zoned pyroxene grains throughout, rare grains of exsolved pigeonite, ilmenite, Ti-chromite, troilite, silica polymorph and iron metal. Shock melt domains are common containing plagioclase grains set in a matrix of quench crystals. A single "granophyre" clast (100 microns across) composed of intergrown K-feldspar+silica was observed. Secondary barite and iron oxide/hydroxide were detected.

Geochemistry: (C. Agee and M. Spilde, UNM; A. Greshake and P. Czaja, MNB; A. Irving and S. Kuehner, UWS). Olivine Fa39.6±7.8, Fe/Mn=94±8, n=49; low-Ca pyroxene Fs37.4±7.0Wo4.7±1.6, Fe/Mn=57±8, n=30; pigeonite Fs34.4±9.4Wo12.9±4.0, Fe/Mn=60±5, n=15; high-Ca pyroxenes Fs26.9±10.9Wo38.4±4.6, Fe/Mn=58±9, n=15; plagioclase An96.6±0.6Ab3.3±0Or0.2±0.15, n=17. Bulk composition (R. Korotev, WUSL). INAA on 18 subsamples gave the following mean values: Na2O=0.331, CaO=16.3, FeO=4.52 (all wt%); Sc=8.67, Cr=587, Co=12.48, Ni=81, La=2.09, Nd=3.2, Sm=0.984, Eu=0.772, Lu=0.111, Hf=0.63, Ir=0.0037, Au=0.0021, Th=0.29, U=0.16 (all ppm). Oxygen Isotopes, laser fluorination (K. Ziegler, UNM), 12 analyses on 5 acid-washed aliquots gave mean values δ17O=2.963±0.126, δ18O=5.646±0.316, Δ17O=-0.018±0.06 (linearized, all permil).

Classification: Achondrite (lunar, feldspathic breccia)

Specimens: A total of 30 g of material including two probe mounts are on deposit at UNM. The remainder is divided between Dr. J. Piatek and Mr. M. Morgan, with Dr. J. Piatek holding the main portion of the largest stone and the other five stones.

Data from:
  MB101
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P August 2012
Mass (g):503
Pieces:6
Class:Lunar (feldsp. breccia)
Fayalite (mol%):39.6±7.8
Ferrosilite (mol%):37.4±7.0, 34.4±9.4, 26.9±10.9
Wollastonite (mol%):4.7±1.6, 12.9±4.0, 38.4±4.6
Classifier:C. Agee, UNM
Type spec mass (g):30
Type spec location:UNM
Main mass:Jay Piatek
Comments:Submitted by C. Agee
Plots: O isotopes:  
Institutions
   and collections
JSC: Mailcode KT, 2101 NASA Parkway, NASA Johnson Space Center, Houston, TX 77058, United States; Website (institutional address; updated 3 Sep 2013)
MNB: Museum für Naturkunde, Invalidenstrasse 43, D-10115 Berlin, Germany (institutional address)
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)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 101, MAPS 50, 1661, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Russ Opdahl   
Geography:

Morocco
Coordinates:Unknown.

Statistics:
     This is 1 of 1386 approved meteorites from Morocco (plus 16 unapproved names) (plus 1 impact crater)

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