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Northwest Africa 12217
Basic information Name: Northwest Africa 12217
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12217
Observed fall: No
Year found: 2015
Country: (Northwest Africa)
Mass:help 148 g
Recommended:  Achondrite-ung    [explanation]

This is 1 of 83 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 12 Nov 2018
Writeup from MB 107:

Northwest Africa 12217 (NWA 12217)

(Northwest Africa)

Purchased: 2015

Classification: Ungrouped achondrite

History: Purchased by Jay Piatek in 2015 from a Moroccan meteorite dealer.

Physical characteristics: Single stone, partially covered with black fusion crust. The surface also exposes a fragmental breccia interior with coarse cream-colored grains crosscut by fine dark veinlets. Saw-cut surface reveals light colored angular mineral fragments up to 1 cm in size bounded by darker gray, fine grained material. A prominent, partially oxidized metal grain was visible in the saw cut surface.

Petrography: (C. Agee, UNM) Backscatter electron mapping gives the approximate modal abundances: 93% olivine, 4% pyroxene, with minor chromite, troilite, Fe-metal, alkali feldspar, plagioclase, silica, and fluorapatite, primarily occupying boundaries and pockets between the larger olivine grains.

Geochemistry: (C. Agee, UNM) Olivine Fa9.6±2.5, Fe/Mn=36±3, n=19; low-Ca pyroxene Fs19.3±0.8Wo2.6±0.4, Fe/Mn=25±1, n=8; alkali feldspar An2.9±1.1Or56.2±10.3Ab41.0±10.1, n=18; plagioclase An43.5±3.7Or1.6±0.3Ab54.9±4.0, n=4; apatite CaO=46.3±0.4, MgO=3.6±0.0, FeO=0.27±0.01, Na2O=2.5±0.1, P2O5=45.3±0.7, F=0.53±0.04, Cl (not detected) all wt%, n=3; metal Fe=97.8±0.6, Ni=2.1±0.6 (wt%), n=5; chromite Al2O3=3.4±0.1, Cr2O3=64.4±0.8, MgO=7.9±0.4, MnO=0.69±0.05, FeO=19.4±0.3 (wt%), n=3. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ18O= 3.723, 3.869, 3.660; δ17O= 1.793, 1.884, 1.796; Δ17O= -0.173, -0.159, -0.136 (linearized, all per mil, TFL slope=0.528).

Classification: Ungrouped achondrite, dunite breccia. The oxygen isotope values of this meteorite plot midway between the eucrite fractionation line (EFL) and the angrite fractionation line (AFL), however its mineralogy is unlike HEDs or angrites; in particular this meteorite possesses alkali feldspar and lacks Ca-rich plagioclase. Furthermore, the Fe/Mn of this meteorite is somewhat lower than for HEDs and much lower than angrites. Brachinites have similar oxygen isotope values, however this meteorite has olivine with much lower Fa and Fe/Mn values than brachinites.

Specimens: 20.7 g including a probe mount on deposit at UNM, Jay Piatek holds the main mass.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2015
Mass (g):148
Shock stage:high
Weathering grade:low
Fayalite (mol%):9.6±2.5
Ferrosilite (mol%):19.3±0.8
Wollastonite (mol%):2.6±0.4
Classifier:C. Agee, UNM
Type spec mass (g):20.7
Type spec location:UNM
Main mass:Jay Piatek
Comments:Field name JP-94; submitted by C. Agee
Plots: O isotopes:  
   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)
References: Published in Meteoritical Bulletin, no. 107, in preparation (2018)
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     This is 1 of 6631 approved meteorites from (Northwest Africa) (plus 2036 unapproved names)

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