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Northwest Africa 12908
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:help 86 g
Classification
  history:
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 197 approved meteorites (plus 1 unapproved name) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 7 Nov 2019
Writeuphelp
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:
Place of purchase:Chenzhou, China
Date:P 2019
Mass (g):86
Pieces:1
Class:Martian (shergottite)
Shock stage:high
Weathering grade:low
Ferrosilite (mol%):45.6±17.2
Classifier:C. Agee, UNM
Type spec mass (g):18.7
Type spec location:UNM
Main mass:Zuokai Ke
Comments:Field name KE-51; submitted by C. Agee
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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7005 approved meteorites from (Northwest Africa) (plus 2002 unapproved names)

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