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Northwest Africa 15257
Basic information Name: Northwest Africa 15257
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15257
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 920 g
Recommended:  Eucrite    [explanation]

This is 1 of 588 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 14 Sep 2022
Writeup from MB 111:

Northwest Africa 15257 (NWA 15257)

(Northwest Africa)

Purchased: 2022

Classification: HED achondrite (Eucrite)

History: Many fragments were found (main masses: 496, 160, 154, and 60 g) in northwest Africa. Adrián Contreras Gómez (CRATER meteorites) purchased the samples from Ali Hnini in 2022.

Physical characteristics: Samples are brecciated and light gray, and some show a thin black fusion crust.

Petrography: Description and classification (A. Love, App) Sample is a polymict breccia composed of 2mm equilibrated lithic fragments and related mineral debris. Lithic fragments have subophitic, cumulate, granulitic textures and shock melted textures. Pyroxenes are exsolved. Additional minerals are: chromite, ilmenite, a Si polymorph, fayalitic olivine, troilite, merrillite and rare Fe metal grains.

Geochemistry: (A. Love, App) Olivine (Fa78.7±5.8, Fe/Mn=38.1±2.2, n=3); low Ca pyroxene (Fs54.0±11.3Wo2.1±0.8, Fe/Mn=30.5±1.5, n=20); pigeonite (Fs46.0Wo18.3, Fe/Mn=31.8, n=1); high Ca pyroxene (Fs26.2±5.2Wo41.3±2.5, Fe/Mn=30.1±2.8, n=9); plagioclase (An91.3±4.4Or0.3±0.3, n=8).

Classification: HED achondrite (polymict eucrite breccia M-S3 low weathering). Based on textural diversity of lithic clasts and unequilibrated compositions, this is a polymict eucrite breccia.

Specimens: Adrián Contreras Gómez (CRATER meteorites) holds the main masses. Many small fragments weighing 22.34g and a polished thin section and mount are on deposit at App.

Data from:
  Table 0
  Line 0:
Date:P 2022
Mass (g):920
Shock stage:M-S3
Weathering grade:low
Fayalite (mol%):78.7±5.8
Ferrosilite (mol%):54.0±11.3; 46.0; 26.2±5.2
Wollastonite (mol%):2.1±0.8; 18.3; 41.3±2.5
Classifier:A. Love, App
Type spec mass (g):22.34
Type spec location:App
Main mass:Adrián Contreras Gómez (CRATER Meteorites)
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 Meteoritical Bulletin, no. 111, in preparation (2022)
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     This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names)

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