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Northwest Africa 13740
Basic information Name: Northwest Africa 13740
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13740
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 405 g
Meteoritical Bulletin:  MB 110  (2022)  Mesosiderite
Recommended:  Mesosiderite    [explanation]

This is 1 of 276 approved meteorites classified as Mesosiderite.   [show all]
Search for other: Mesosiderites, Metal-rich meteorites
Comments: Approved 28 Mar 2021
Writeup from MB 110:

Northwest Africa 13740 (NWA 13740)


Purchased: 2020

Classification: Mesosiderite

History: Fabien Kuntz purchased the 405.3 g sample from a dealer in Algeria in 2020.

Physical characteristics: The sample is rounded in shape and has a dark reddish-brown, weathered exterior. The interior is a breccia composed of silicates and abundant metal.

Petrography: Description and classification (A. Love, App) Sample is a breccia composed of (vol%): cm-sized, angular-irregular-shaped lithic and orthopyroxene clasts (~60) set within a network of irregular-shaped, mm-sized metal grains (~40) and comminuted mixture of orthopyroxene, merrillite and plagioclase. A single subophitic clast has an average grain size 0.75 mm. Modal percentages (vol%) of silicates: orthopyroxene (68), plagioclase (28), olivine (3) and an irregular-lath-shaped silica polymorph (1). One olivine shows a thin reaction corona whereas another has been completely replaced. Matrix areas are thoroughly recrystallized and show abundant sutured grain boundaries. Additional minerals are: a silica polymorph, troilite, chromite and ilmenite.

Geochemistry: Olivine (Fa34.1, Fe/Mn=41.3, n=1); low Ca pyroxene (Fs32.9±3.3Wo3.0±0.5, Fe/Mn=26.9±2.3, n=13); high Ca pyroxene (Fs16.1±1.1Wo41.8±1.4, Fe/Mn=21.1±2.7, n=5); plagioclase (An95.5±1.7Or0, n=6).

Classification: Mesosiderite (estimated class A3). Mesosiderite Class A based on texture, metal abundance, magnetic susceptibility and modal abundance (silicates) of plagioclase and Opx. Metamorphic grade 3 based on recrystallization textures within matrix and between clasts and matrix and lack of pigeonite and the partial to complete replacement of olivine.

Specimens: Fabien Kuntz holds the main mass. A slice weighing 25.3 g and a polished mount are on deposit at App.

Data from:
  Table 0
  Line 0:
Date:P 2020
Mass (g):405.3
Weathering grade:low
Fayalite (mol%):34.1
Ferrosilite (mol%):32.9±3.3; 16.1±1.1
Wollastonite (mol%):3.0±0.5; 41.8±1.4
Magnetic suscept.:5.73
Classifier:A. Love, App
Type spec mass (g):25.3
Type spec location:App
Main mass:Fabien Kuntz
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)
Kuntz: Fabien Kuntz, France; Website (private address)
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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     This is 1 of 1364 approved meteorites from Algeria (plus 31 unapproved names) (plus 4 impact craters)

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