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Northwest Africa 12690 | |||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 12690 This is an OFFICIAL meteorite name. Abbreviation: NWA 12690 Observed fall: No Year found: 2019 Country: (Northwest Africa) Mass: 9.1 kg | ||||||||||||||||||||||||||||
Classification history: |
This is 1 of 319 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||||||||
Comments: | Approved 18 Aug 2019 | ||||||||||||||||||||||||||||
Writeup |
Writeup from MB 108:
Northwest Africa 12690 (NWA 12690) NWA Find: 2018 Dec Classification: Martian meteorite (Shergottite) History: The meteorite was reportedly found December 16, 2018, by a Malian nomad near Achemeleml and purchased in 2019 by Ben Hoefnagels in Niger. One fragment was analyzed by Ansgar Greshake at MNB and the analysis of a second fragment was initiated by Ben Hoefnagels and conducted by Paul Carpenter, WUSTL. Physical characteristics: Large greenish individual with some fusion crust. Petrography: The meteorite has a diabasic texture and is predominantly composed of up to 3 mm sized calcic pyroxenes that show complex patchy compositional zoning and equally sized maskelynite grains. Minor phases include ilmenite, ulvospinel, merrillite, and pyrrhotite. Some myrmekitic breakdown assemblages consisting of Fe-rich pyroxene, fayalite, and silica are present. The meteorite is highly shocked and contains abundant shock melt pockets. Geochemistry: (A. Greshake, MNB) pigeonite: Fs53.2±18.9Wo13.6±2.6 (Fs27.2-76.2Wo8.9-18.1, n=26, FeO/MnO=26-42); augite: Fs28.5±4.4Wo28.7±5.9 (Fs24.5-37.1Wo20.8-35.2, n=15, FeO/MnO=26-34); maskelynite: An62.3Ab37.4Or0.3, n=22; P. Carpenter (Washington University, St. Louis) Ca-pyroxene cores: Wo24.8-35.0En42.2-49.2Fs21.0-26.2, N=3, FeO/MnO 28-30; Ca-pyroxene rims: Wo14.7-40.3En2.3-19.6Fs57.4-72.0, N=3, FeO/MnO 38-43; fayalite: Fa96.5, N=1, maskelynite: An61.4Ab38.4Or0.2, N=1. Classification: Martian (diabasic shergottite) Specimens: 34.4 g are at MNB and 14.36 g are at UWB; 20 g with Mr. B. Hoefnagels. Main mass with anonymous owner. | ||||||||||||||||||||||||||||
Data from: MB108 Table 0 Line 0: |
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Institutions and collections |
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011) UWB: University of Washington, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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Geography: |
Statistics: This is 1 of 9627 approved meteorites from (Northwest Africa) (plus 1865 unapproved names) | ||||||||||||||||||||||||||||
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Revision history: |
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