|Northwest Africa 8402|
|Basic information||Name: Northwest Africa 8402|
This is an OFFICIAL meteorite name.
Abbreviation: NWA 8402
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass: 23.85 kg
This is 1 of 4 approved meteorites classified as Mesosiderite-A3. [show all]
Search for other: Class A mesosiderites, Mesosiderites, and Metal-rich meteorites
|Comments:||Approved 29 May 2014|
Writeup from MB 103:
Northwest Africa 8402 (NWA 8402)
Classification: Mesosiderite (group A3)
History: Purchased from S. Haddany in March 2014
Physical characteristics: Single stone with irregular dark gray-brown exterior. Saw cut reveals numerous spherical metal domains >1 mm, but also abundant fine-grained metal distributed uniformly throughout. Silicate clasts >1 mm, some fragmental, others rounded or texturally equilibrated. Abundant fine-grained silicate groundmass.
Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows pyroxene making up approximately 75% of the silicate portion of this meteorite, ~25% plagioclase, ~5% silica. Pyroxene grains in section up to 1 mm, some poikiloblastic; plagioclase up to 500 μm, but also finer-grained intergranular; numerous intersertal silica laths up to 200 μm in length and ~10 μm thick; no olivine detected. Metal makes up approximately 40% of this meteorite and is primarily segregated into domains >1 mm, although there are scattered smaller (~10 μm) grains throughout the silicate domains. No brecciation observed. Minor oxidation of metal and a few weathering veinlets.
Geochemistry: (C. Agee and N. Muttik, UNM) Low-Ca pyroxene Fs37.4±0.3Wo3.2±0.1, Fe/Mn=22±1, n=3; high-Ca pyroxene Fs18.6±0.1Wo39.9±0.0, Fe/Mn=18±0, n=2; plagioclase An90.2±1.8Ab9.2±1.8Or0.6±0.1, n=6; kamacite Fe=93.7±0.1, Ni=6.2±0.0 (wt%), n=2; taenite Fe=62.0±5.8, Ni=37.9±5.8 (wt%), n=2.
Classification: Mesosiderite-A3. Relatively high abundance of plagioclase and silica consistent with group A. Segregated metal, presence of some texturally and chemically equilibrated silicates, and absence of brecciation consistent with type 3.
Specimens: 29.7 g including a probe mount on deposit at UNM, DPitt holds the main mass.
UNM: Institute of Meteoritics
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
|References:||Published in Meteoritical Bulletin, no. 103, in preparation (2014)|
This is 1 of 5759 approved meteorites from (Northwest Africa) (plus 2068 unapproved names)
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