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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
Recommended:  Mesosiderite    [explanation]

This is 1 of 233 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 Meteoritical Bulletin, no. 110, in preparation (2021)
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Ryan Upchurch   


     This is 1 of 1213 approved meteorites from Algeria (plus 29 unapproved names) (plus 4 impact craters)

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