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Northwest Africa 13446
Basic information Name: Northwest Africa 13446
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13446
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 6.48 kg
Classification
  history:
Recommended:  Achondrite-ung    [explanation]

This is 1 of 106 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 1 Nov 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13446 (NWA 13446)

Algeria

Purchased: 2020 Jun

Classification: Ungrouped achondrite

History: Purportedly found in Algeria and purchased by Habib Naji in June 2020 from a dealer in Adrar, Algeria.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) The specimen has an igneous cumulate texture and consists predominantly of zoned olivine (~90 vol.%) with intercumulus assemblages composed of low-Ca pyroxene (mostly pigeonite), subcalcic augite and sodic plagioclase-like glass with accessory chromite, troilite and very rare spherical grains of metal (kamacite and taenite).

Geochemistry: Olivine (Fa19.8±3.7, range Fa15.8-27.9, FeO/MnO = 47-54, N = 11), low-Ca pyroxene (Fs28.8Wo4.6, FeO/MnO = 26), pigeonite (Fs26.6±4.4Wo10.4±4.7, range Fs18.3-30.6Wo6.5-18.9, FeO/MnO = 26-30, N = 6), subcalcic augite (Fs34.2±6.7Wo27.2±5.0, range Fs27.3-43.3Wo23.0-34.2, FeO/MnO = 27-35, N = 4), plagioclase-like glass (Ab65.4-86.0An15.7-5.8Or18.9-8.2, N = 4), kamacite (Ni = 1.6 wt.%), taenite (Ni = 36.4 wt.%). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 3.638. 3.614, 3.623; δ18O 4.887, 4.859, 4.947; Δ17O 1.058, 1.049, 1.012 per mil (all data linearized).

Classification: Achondrite (igneous, ultramafic, ungrouped). This specimen is an almost metal-free, olivine-dominated igneous achondrite with oxygen isotope affinities to L chondrites. Olivine exhibits compositional zoning from core values typical of H chondrites to rim values more typical of L chondrites, and intercumulus pyroxene also exhibits zoning from pigeonite cores to subcalcic augite rims.

Specimens: 54 g including one polished thin section at UWB; remainder with Mr. H. Naji.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Adrar
Date:P 2020 Jun
Mass (g):6484
Pieces:several
Class:Achondrite-ung
Shock stage:low
Weathering grade:low
Fayalite (mol%):19.8±3.7
Ferrosilite (mol%):28.8; 26.6±4.4; 34.2±6.7
Wollastonite (mol%):4.6; 10.4±4.7; 27.2±5.0
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):54.0
Type spec location:UWB
Main mass:H. Naji
Comments:Work name HN 630; submitted by A. Irving
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)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Dirk Hohmann      
Geography:

Algeria
Coordinates:Unknown.

Statistics:
     This is 1 of 1113 approved meteorites from Algeria (plus 27 unapproved names) (plus 4 impact craters)

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