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Northwest Africa 13432
Basic information Name: Northwest Africa 13432
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13432
Observed fall: No
Year found: 2020
Country: (Northwest Africa)
Mass:help 4.46 kg
Classification
  history:
Recommended:  Winonaite    [explanation]

This is 1 of 43 approved meteorites classified as Winonaite.   [show all]
Search for other: Primitive achondrites, Winonaites
Comments: Approved 14 Oct 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13432 (NWA 13432)

(Northwest Africa)

Purchased: 2020 Mar

Classification: Primitive achondrite (Winonaite)

History: Purchased by Darryl Pitt in March 2020 from a Moroccan dealer.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Metamorphic triple grain junction texture (mean grainsize ~250 µm). Aggregate of olivine, orthopyroxene, fluoro-edenitic amphibole (as oikocrysts enclosing other mineral grains), sodic plagioclase, diopside and kamacite plus minor fluorapatite, graphite and schreibersite.

Geochemistry: Olivine (Fa3.0-3.3, FeO/MnO = 16-22, N = 5), orthopyroxene (Fs 3.5-3.8Wo1.7-1.9, FeO/MnO = 12-14, N = 5), diopside (Fs1.1-1.3Wo44.8-45.8, FeO/MnO = 9-12, N = 3), plagioclase (An20.8Ab76.5Or2.6). A total of 53 WDS analyses were obtained on the fluoro-edenite amphibole: it is very homogeneous in composition throughout the studied thin section. It has a mean formula (with (OH) by difference): (Na0.836K0.101) (Ca1.749Na0.176 Fe2+0.068 Mn0.007) (Mg4.799Ti0.104Cr0.04Al0.036Fe2+0.021)(Si6.954Al1.046)O22 [F1.905(OH)0.078Cl0.016]. Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 2.272, 2.016, 2.196; δ18O 5.328, 4.855, 5.196; Δ17O -0.541, -0.548, -0.548 per mil (all data linearized).

Classification: Winonaite. This specimen is unusual because of the presence of fluoro-amphibole, as also observed in winonaite Hammadah al Hamra 193 (Floss et al., 2007).

Specimens: 23.8 g including one polished thin section at UWB; remainder with DPitt.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2020 Mar
Mass (g):4459
Pieces:5
Class:Winonaite
Shock stage:low
Weathering grade:low
Fayalite (mol%):3.0-3.3
Ferrosilite (mol%):3.5-3.8; 1.1-1.3
Wollastonite (mol%):1.7-1.9; 44.8-45.8
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):23.8
Type spec location:UWB
Main mass:D. Pitt
Comments:Work nameMVCH 502; 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)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7385 approved meteorites from (Northwest Africa) (plus 1955 unapproved names)

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