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Northwest Africa 13640
Basic information Name: Northwest Africa 13640
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13640
Observed fall: No
Year found: 2020
Country: Mauritania
Mass:help 935 g
Recommended:  Winonaite    [explanation]

This is 1 of 85 approved meteorites (plus 1 unapproved name) classified as Winonaite.   [show all]
Search for other: Primitive achondrites, Winonaites
Comments: Approved 28 Mar 2021
Writeup from MB 110:

Northwest Africa 13640 (NWA 13640)


Purchased: 2020

Classification: Primitive achondrite (Winonaite)

History: A single 935 g sample was found and subsequently purchased by Carlos Muñecas in Mauritania in October 2020.

Physical characteristics: Sample is oriented with dark brown fusion crust coating one side of the flattened disc-shaped stone. The back side of the sample has a large area of exposed FeNi that covers half the surface. The cut face shows the sample is a crystalline mixture of FeNi metal grains and coarse-grained silicates.

Petrography: Description and classification (A. Love, App) escription and classification (A. Love, App) Sample shows poikiloblastic texture composed of (vol%): 0.5-1.0 cm-sized enstatite(49) and diopside(6) oikocrysts enclosing 165 µm (ave. grainsize) olivine chadacrysts(22), anhedral twinned albitic plagioclase(14); FeNi metal(6); troilite(4). Olivine also occurs in lumps of equigranular grains interstitial to oikocrysts. Additional minerals are: graphite (associated with silicates and metals), schreibersite, apatite and possible amphibole.

Geochemistry: (A. Love, App) Olivine (Fa3.1±0.2, Fe/Mn=17.1±1.4, n=27), enstatite (Fs3.6±0.7Wo1.5±0.6, Fe/Mn=12.8±1.6, n=21); diopside (Fs1.4±0.2Wo45.0±0.4, Fe/Mn=10.5±2.2, n=16), oligoclase (An21.3±0.5Or2.7±0.2, n=12).

Classification: Primitive achondrite (Winonaite) Based on abundance of metal and composition of silicates, sample is a winonaite. Grainsize and texture are comparable to Hammadah al Hamra 193.

Specimens: Carlos Muñecas (Expometeoritos) holds the main mass. A 28.70 g slice and a polished thin section are on deposit at App.

Data from:
  Table 0
  Line 0:
Place of purchase:Mauritania
Date:P 2020
Mass (g):935
Shock stage:low
Weathering grade:low
Fayalite (mol%):3.1±0.2
Ferrosilite (mol%):3.6±0.7; 1.4±0.2
Wollastonite (mol%):1.5±0.6; 45.0±0.4
Magnetic suscept.:5.53
Classifier:Anthony Love
Type spec mass (g):28.70
Type spec location:App
Main mass:Carlos Muñecas (Expometeoritos)
Comments:Submitted by Anthony Love
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
References: Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4
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Public domain photographs:
Anthony Love   


     This is 1 of 212 approved meteorites from Mauritania (plus 2 unapproved names) (plus 2 impact craters)

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