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Northwest Africa 12908 | |||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 12908 This is an OFFICIAL meteorite name. Abbreviation: NWA 12908 Observed fall: No Year found: 2019 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||
Classification history: |
This is 1 of 298 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||||||
Comments: | Approved 7 Nov 2019 | ||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 108:
Northwest Africa 12908 (NWA 12908) (Northwest Africa) Purchased: 2019 Classification: Martian meteorite (Shergottite) History: Purchased by Zuokai Ke from a Moroccan dealer in Chenzhou, China, in May 2019. Physical characteristics: Single stone, brownish sand blasted exterior with no fusion crust. Cut surface reveals greenish-yellow grains and dark gray grains or domains. Petrography: (C. Agee, UNM; X. Gu, CSU-China) The two major phases in this meteorite are clinopyroxene and maskelynite. Ubiquitous minor phases are merrillite, apatite, titanomagnetite, ilmenite and troilite. Trace amounts of baddelyite, taenite, chalcopyrite, and molybdenite were detected. The clinopyroxene has a modal abundance of approximately 60%, with significant core to rim zoning observed in backscatter electron images indicating an igneous crystallization trend with Mg-rich pigeonite cores, mantled by augite, and rimmed with ferropigeonite. Clinopyroxene average grain size is approximately 300-500 μm. Maskelynite has modal abundance of approximately 30%, most grains are thin and elongate with maximum length ~1 mm. Merrilite is more abundant than apatite in this sample. Geochemistry: (C. Agee, UNM; X. Gu, CSU-China: (C. Agee, UNM) Clinopyroxene Fs45.6±17.2Wo22.6±7.2, core to rim range Fs31.1Wo14.0 (Mg-pigeonite) Fs22.6Wo37.0 (augite) - Fs73.3Wo17.6 (ferropigeonite), Fe/Mn=38±5, n=24; maskelynite An47.4±4.8Ab48.9±3.9Or3.7±1.4, n=13. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ18O= 4.728, 4.967,4.670; δ17O= 2.780, 2.896, 2.738; Δ17O= 0.284, 0.273, 0.272 (linearized, all per mil, TFL slope=0.528). Classification: Geochemically evolved pyroxene-phyric basalt, clinopyroxene compositional zoning trends are similar to QUE 94201. Likely paired with NWA 12522. Specimens: 18.7 g including a probe mount on deposit at UNM, Zuokai Ke holds the main mass. | ||||||||||||||||||||||||||
Data from: MB108 Table 0 Line 0: |
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Plots: | O isotopes: | ||||||||||||||||||||||||||
Institutions and collections |
UNM: Institute of Meteoritics
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015) CSU: Department of Geosciences Colorado State University Fort Collins, CO 80523 , United States (institutional address; updated 21 Jan 2019) |
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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 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) |