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Northwest Africa 15857
Basic information Name: Northwest Africa 15857
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15857
Observed fall: No
Year found: 2021
Country: (Northwest Africa)
Mass:help 800 g
Recommended:  Aubrite    [explanation]

This is 1 of 81 approved meteorites classified as Aubrite.   [show all]
Search for other: Achondrites, Aubrites, Enstatite achondrites, and Enstatite-rich meteorites
Comments: Approved 15 Oct 2023
Writeup from MB 112:

Northwest Africa 15857 (NWA 15857)

(Northwest Africa)

Purchased: July 2021

Classification: Enstatite achondrite (Aubrite)

History: Purchased in July 2021 by Geologist Juan Avilés Poblador, Roger Jones, and Sean Mahoney from a meteorite dealer in south Morocco.

Physical characteristics: Many grayish to grayish-white pieces and fragments (some contain orange-colored spots due to weathering). Some fragments contain minor fusion crust, others contain a network of dark shock melt veins on their surfaces.

Petrography: (D. Sheikh, Cascadia) Specimen represents a coarse-grained breccia comprised of strongly shocked mm to cm-sized enstatite grains (some containing inclusions of diopside) set within a matrix containing dark shock melt veins. Accessory phases identified include Ti-bearing troilite, daubréelite, and Si-bearing kamacite. Forsterite and plagioclase were not observed in the section analyzed.

Geochemistry: Enstatite (Fs0.1±0.1Wo0.5±0.2, range Fs0.1-0.2Wo0.4-0.8, n=15), Diopside (Fs0.1±0.1Wo43.9±2.6, range Fs0.1-0.2Wo42.1-45.8, n=3).

Classification: Achondrite (Aubrite)

Specimens: 20.5 g at Cascadia, main mass with Sean Mahoney (200 g), Geologist Juan Avilés Poblador (350 g), and Roger Jones (250 g).

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P July 2021
Mass (g):800
Shock stage:high
Weathering grade:moderate
Ferrosilite (mol%):0.1±0.1, 0.1±0.1
Wollastonite (mol%):0.5±0.2, 43.9±2.6
Classifier:D. Sheikh, Cascadia
Type spec mass (g):20.5
Type spec location:Cascadia
Main mass:Geologist Juan Avilés Poblador, Roger Jones, and Sean Mahoney
Comments:CML 1584; submitted by Daniel Sheikh
   and collections
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
References: Published in Meteoritical Bulletin, no. 112, in preparation (2023)
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     This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names)

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