|Northwest Africa 10401|
|Basic information||Name: Northwest Africa 10401|
This is an OFFICIAL meteorite name.
Abbreviation: NWA 10401
Observed fall: No
Year found: 2015
Country: (Northwest Africa)
Mass: 354 g
This is 1 of 62 approved meteorites classified as Lunar. [show all]
Search for other: Lunar meteorites
|Comments:||Approved 26 Dec 2015|
Writeup from MB 104:
Northwest Africa 10401 (NWA 10401)
Classification: Lunar meteorite
History: Purchased by Steve Arnold from a dealer in Ouarzarete, Morocco in 2015.
Physical characteristics: Two stones totaling 354 g (218 and 136 g). A sawed piece from one of the stones reveals a very fine-grained, light-gray groundmass that is cross-cut by several shock melt veins. Larger white clasts within the groundmass are present.
Petrography: A. Hilton (CoW), J. Gross (Rut). This meteorite is an anorthositic troctolite with a granulitic texture. It contains plagioclase (59-65%), olivine (23-26%), orthopyroxene, and clinopyroxene (pyx total: 12-15%) as the main silicate phases. Accessory grains of spinel were observed. Microprobe examination shows two particularly large clasts (diameters 3.1-4.7 mm) surrounded by a light-gray, fine-grained matrix and many smaller clasts (0.1-0.8 mm). The sample is crosscut by an abundant number of thin shock melt veins. The veins show compositional variation as well as partial assimilation of surrounding grains in some areas and are homogeneous in others. Plagioclase grains (0.2-0.8 mm) are angular and sub-euhedral in shape, while mafic clasts rich in olivine and pyroxene (0.1-0.3 mm) are composed of small (<10-35 μm) anhedral olivine and pyroxene grains. Single anhedral grains of olivine and pyroxene are also present in the sample, including some that exhibit pyroxene exsolution lamellae. The matrix is composed of small, granular, anhedral grains of olivine and pyroxene that appear to outline grain boundaries of plagioclase fragments.
Geochemistry: J. Gross (Rut) and A. Hilton (CoW). Olivine Fa18.6±2 (N=180), Fe/Mn=88.1±8.3; Orthopyroxene: Fs15.5±2Wo3.1±0.6En81.4±4.7, Fe/Mn=49.3±6 (N=48); Clinopyroxene: Fs9.0±1.4Wo41.3±7.9En 49.7±6.8, Fe/Mn=37.2±4 (N = 20); Plagioclase An96.6±0.3Ab2.9±0.6Or0.1±0.05 (N=254). The shock melt vein (defocused electron beam as proxy for bulk composition) has an average composition of: Na2O = 0.27±0.1, MgO = 9.7±0.3, SiO2 = 45±0.8, Al2O3 = 26±0.6, P2O5 = 0.02±0.04, K2O = 0.01±0.01, CaO = 15±6, TiO2 = 0.12±0.03, MnO = 0.06±0.04, FeO = 4.1±0.3, BaO = 0.01±0.03 Cr2O3 = 0.13±0.03, NiO = 0.02±0.02, N=74. Bulk composition (R. Korotev, WUSL): INAA on a 99 mg fragment gave FeO 6.1 wt%, Na2O 0.24 wt%; Sc 8.7, Cr 1300, Ni 124, La 0.65, Sm 0.38, Eu 0.55, Yb 0.37, Th 0.07, all in ppm.
Classification: Lunar (anorthositic troctolitic breccia with granulitic texture)
Specimens: 20 g at TCU, thick section probe mount at RU; Peter Scherff holds the main mass.
TCU: Oscar E. Monnig Collection, Department of Geology, Texas Christian University, Ft. Worth, TX 76129, United States; Website (institutional address; updated 24 Feb 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
Rut: Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States (institutional address)
CoW: College of Wooster, Department of Geology 944 College Mall Wooster, OH 44691, United States (institutional address; updated 1 Nov 2015)
|References:||Published in Meteoritical Bulletin, no. 104, in preparation (2015)|
This is 1 of 5322 approved meteorites from (Northwest Africa) (plus 2131 unapproved names)
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