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Northwest Africa 14684
Basic information Name: Northwest Africa 14684
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14684
Observed fall: No
Year found: 2020
Country: (Northwest Africa)
Mass:help 3 kg
Recommended:  Mesosiderite-A3    [explanation]

This is 1 of 9 approved meteorites classified as Mesosiderite-A3.   [show all]
Search for other: Class A mesosiderites, Mesosiderites, and Metal-rich meteorites
Comments: Approved 6 Aug 2022
Writeup from MB 111:

Northwest Africa 14684 (NWA 14684)

(Northwest Africa)

Purchased: 2020

Classification: Mesosiderite (group A3)

History: Purchased January, 2020, by Mark Lyon from a northwest African dealer

Physical characteristics: A single stone without fusion crust, cut surface reveals ubiquitous ameboid shaped metal set against a dark coarse groundmass.

Petrography: (A. Ross, UNM; D. Dickens, NMMS; C. Agee, UNM) Microprobe examination of a polished mount shows pyroxene is the dominant phase, with significant amounts of plagioclase also present. Some pyroxene grains display exsolution lamellae. Plagioclase is often poikilitically enclosed in pyroxene grains. Image analysis of a section of a polished mount shows the silicate portion is composed of ~65% pyroxene, ~30% plagioclase, with remaining ~5% a mix of minor phases; silica, ilmenite, merrillite, chromite, and troilite. No olivine was detected. Metal makes up approximately 39% of this meteorite and is primarily segregated into irregular ameboid domains of approximately 1 mm to 2 mm, with less frequent larger grains ubiquitously distributed throughout the silicate domains. Both kamacite and taenite are present. No significant brecciation observed.

Geochemistry: (A. Ross, UNM) Low-Ca pyroxene Fs33.2±0.8Wo3.8±0.8, Fe/Mn=26±1, n=4; high-Ca pyroxene Fs29.9±1.3Wo10.8±7.1, Fe/Mn=25±1, n=2; plagioclase An88.7±3.0Ab10.7±2.7Or0.6±0.3, n=4;

Classification: Mesosiderite-A3. Relatively high percentage of plagioclase and silica consistent with group A. Segregated metal, equilibrated silicates, lack of significant brecciation consistent with type 3.

Specimens: 27.6 g including a probe mount on deposit at UNM, Mark Lyon holds the main mass.

Data from:
  Table 0
  Line 0:
Place of purchase:Algeria
Date:P 2020
Mass (g):3000
Shock stage:low
Weathering grade:moderate
Ferrosilite (mol%):33.2±0.8, 29.9±1.3
Wollastonite (mol%):3.8±0.8, 10.8±7.1
Classifier:C. Agee, UNM; D. Dickens, NMMS
Type spec mass (g):27.6
Type spec location:UNM
Main mass:Mark Lyon
Comments:Field Name ML-13; submitted by D. Dickens
   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)
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
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     This is 1 of 8674 approved meteorites from (Northwest Africa) (plus 1882 unapproved names)

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