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Northwest Africa 773
Basic information Name: Northwest Africa 773
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 773
Observed fall: No
Year found: 2000
Country: Western Sahara
Mass:help 633 g
Classification
  history:
NHM Catalogue:  5th Edition  (2000)  Lunar (ol norite)
Meteoritical Bulletin:  MB 85  (2001)  Lunar (cumulate olivine norite with regolith breccia)
MetBase:  v. 7.1  (2006)  Lunar (norite)
Recommended:  Lunar (norite)    [explanation]

This is the only approved meteorite classified as Lunar (norite).
Search for other: Lunar meteorites
Writeuphelp
Writeup from MB 85:

Northwest Africa 773

Western Sahara

Found 2000 September

Lunar Meteorite (cumulate olivine norite with regolith breccia)

Three stones of 359, 224 and 50 g, totaling 633 g were sold to Marvin Killgore (SWML) by nomads who showed him the place of find on a flat dry desert plain near Dchira, Western Sahara.  Mineralogy and classification (T. Fagan, UHaw; M. Killgore, SWML; J. Wittke and T. Bunch, NAU): consists of two distinct lithologies, cumulate rock and regolith breccia; shock stage, S2; weathering grade, W1. Cumulate portion: modes (vol%) are olivine = 54.7, pigeonite = 24.2, augite = 5, feldspar (including minor K-feldspar) = 15.6, opaques (troilite, chromite, Fe-metal, ilmenite) = 0.5; olivine, Fa28–34, mean Fa31, FeO/MnO = 99 ± 11 g/g; pigeonite, En64Wo11, FeO/MnO = 53 ± 6 g/g; augite, En49Wo36, FeO/MnO = 46 ± 6 g/g; plagioclase, An88–91; Ba-rich K-feldspar, An3Ab4Or93 with average BaO = 2.2 wt%. Breccia portion: contains fragments of cumulate portion as well as silica glass, hedenbergitic pyroxene, volcanic rocks, and unusual lithic clasts with fayalite + Ba-rich K-feldspar + silica + plagioclase; olivine and pyroxene in the breccia have a slightly wider compositional range towards lower Mg/(Mg + Fe) than in the cumulate portion of the rock. Chemical composition (D. Mittlefehldt, JSC): KREEP-rich with strong negative Eu-anomaly.  Noble gases (O. Eugster, Physikalisches Institut, Bern): high solar wind component, 4He/20Ne = 9, indicative of regolith material. Specimens: type specimen, 15 g, NHM; main mass SWML.

Data from:
  MB85
  Table 4
  Line 213:
Origin or pseudonym:Dchira, W. Sah.
Date:6 Oct 2000
Latitude:~26°46'N
Longitude:~12°49'W
Mass (g):633
Pieces:3
Class:Lunar
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)
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
NHM: Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom; Website (institutional address; updated 9 Dec 2011)
Bern: University of Bern, University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland (institutional address)
Killgore: Marvin and Kitty Killgore, Southwest Meteorite Laboratory, P.O. Box 95, Payson, AZ 85547, United States; Website (private address)
SWML: Marvin and Kitty Killgore, Southwest Meteorite Laboratory, P.O. Box 95, Payson, AZ 85547, United States; Website (private address)
UHaw: Hawai'i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, United States (institutional address; updated 25 Oct 2011)
Catalogs:
Search for this meteorite in the Natural History Museum collection (U.K.):   
    Require NHM photo
References: Published in Meteoritical Bulletin, no. 85, MAPS 36, A293-A322 (2001)
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Photos:
CreditPhotos
Photos from the Encyclopedia of Meteorites:
Norbert Classen   
Randy Korotev   
Geography:

Western Sahara
Coordinates:
     Catalogue of Meteorites:   (26° 46'N, 12° 49'W)
     Recommended::   (26° 46'N, 12° 49'W)

Statistics:
     This is 1 of 75 approved meteorites from Saguia el Hamra, Western Sahara
     This is 1 of 182 approved meteorites from Western Sahara (plus 18 unapproved names)
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