MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 3 Sep 2023
Search for: Search type: Search limits: Display: Publication:
Text help
Starts with
Sounds like
Falls  Non-NWAs
What's new
  in the last:
Limit to approved meteorite names
Search text:  
Northwest Africa 13858
Basic information Name: Northwest Africa 13858
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13858
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 2.44 kg
Recommended:  Mesosiderite    [explanation]

This is 1 of 256 approved meteorites classified as Mesosiderite.   [show all]
Search for other: Mesosiderites, Metal-rich meteorites
Comments: Approved 6 May 2021
Writeup from MB 110:

Northwest Africa 13858 (NWA 13858)


Purchased: 2020

Classification: Mesosiderite

History: (C. Muñecas, Expometeoritos) Sample was found by a nomad in Algeria (coordinates unknown). This meteorite was eventually purchased by Carlos Muñecas (Expometeoritos) from a dealer in Tindouf in 2020.

Physical characteristics: The sample is dark brown and is irregularly shaped with metal grains protruding through the exterior. The interior is a breccia of metal grains and silicates.

Petrography: Description and classification (A. Love, App) Sample is recrystallized breccia composed of (vol%): rounded-irregular-shaped masses of FeNi metal (25) and anhedral silicates (75) which show sutured grain boundaries and avg. grainsize of 516 µm (n=82). Pyroxenes and plagioclase both show poikiloblastic textures and olivine (2 vol%) contain well-developed reaction coronas. Additional minerals are: inverted pigeonite, high Ca pyroxene exsolution lamellae, merrillite, ilmenite, chromite, and both equant and lath shaped silica polymorphs.

Geochemistry: Olivine (Fa28.2±5.5, Fe/Mn=39.4±2.2, n=4); low Ca pyroxene (Fs30.1±4.1Wo3.6±1.2, Fe/Mn=26.3±2.4, n=21); pigeonite (Fs32.3±1.0Wo6.3±1.3, Fe/Mn=26.9±0.9, n=7); high Ca pyroxene (Fs17.2±1.5Wo39.1±1.7, Fe/Mn=20.7±1.2, n=6); plagioclase (An92.4±1.1Or0.3±0.1, n=6).

Classification: Mesosiderite (estimated class A3). Mesosiderite based on abundance of metal and textures of silicates. Class A based on modal abundance of silicates (28 vol% plagioclase, 64 vol% Opx). Metamorphic type 3 based on recrystallized texture with sutured grain boundaries, absence of fine-grained regions, rare pigeonite and well-developed reaction coronas around olivine.

Specimens: C. Muñecas (Expometeoritos) holds the 1007 g main mass. A polished mount, an endcut and several small fragments weighing 24.32g are on deposit at App.

Data from:
  Table 0
  Line 0:
Date:P 2020
Mass (g):2435
Weathering grade:low
Fayalite (mol%):28.2±5.5
Ferrosilite (mol%):30.1±4.1; 17.2±1.5
Wollastonite (mol%):3.6±1.2; 39.1±1.7
Magnetic suscept.:5.59
Classifier:A. Love, App
Type spec mass (g):24.32
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
Find references in NASA ADS:
Find references in Google Scholar:
Public domain photographs:
Anthony Love      


     This is 1 of 1294 approved meteorites from Algeria (plus 30 unapproved names) (plus 4 impact craters)

Direct link to this page