|Northwest Africa 6578|
|Basic information||Name: Northwest Africa 6578|
This is an OFFICIAL meteorite name.
Abbreviation: NWA 6578
Observed fall: No
Year found: 2010
Mass: 1638 g
This is 1 of 55 approved meteorites classified as Lunar (feldsp. breccia). [show all]
Search for other: Lunar meteorites
|Comments:||Approved 28 Apr 2011|
Writeup from MB 99:
Northwest Africa 6578 (NWA 6578)
Classification: Lunar meteorite (feldspathic breccia)
History: A tan to gray 1638 g stone was purchased in Morocco by Adam Aaronson in 2010.
Physical characteristics: Surface is deeply etched in some places from desert wind abrasion, and the gray colored areas show remnant, translucent fusion crust.
Petrography: (T. Bunch and J. Wittke, NAU; A. Irving and S. Kuehner, UWS): A fine-grained (<0.5 mm, mean grain size = 0.125 mm) partially annealed ultracataclastite (crushed matrix occupies > 90 vol%). The rock is an anorthosite based on the mineral modes of (vol%): anorthite 90, pigeonite 6, olivine 2, metal and FeS 2. Numerous fine-grained (<0.02 mm) micrographic-textured patches contain pigeonite + olivine + plagioclase ± FeS and are roughly flow-oriented. In addition, glassy shock melt veins are sub-parallel to the apparent flow direction. A few elongated clusters of vermiform taenite (<0.05 mm) are interspersed with micrographic intergrowths.
Geochemistry: Plagioclase, An94-96.3; pigeonite, Fs27.7-33.4Wo12.4-14, (FeO/MnO = 73-98); olivine, Fa21.7-44 (FeO/MnO = 78-90); taenite Ni = 9.8-16.7 wt. %. Shock melt glass (avg. of 3 in wt%)is SiO2 = 45.2, Al2O3 = 28.8, CaO = 18.9, FeO = 3.86, MgO = 2.12, Na2O = 0.4, TiO2 = 0.47, MnO = 0.18.
Classification: Achondrite (lunar, granulitic anorthositic breccia). This meteorite is one of the most feldspar-rich lunar specimens (rivaling some Apollo samples), but is texturally unique.
Specimens: A total of 20.2 g is on deposit at NAU. Mr. Adam Aaronson holds the main mass.
NAU: Geology, Bldg 12
Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
|References:||Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]|
This is 1 of 995 approved meteorites from Morocco (plus 8 unapproved names)
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