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Northwest Africa 15856
Basic information Name: Northwest Africa 15856
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15856
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 530 g
Recommended:  Eucrite-pmict    [explanation]

This is 1 of 400 approved meteorites classified as Eucrite-pmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 3 Sep 2023
Writeup from MB 112:

Northwest Africa 15856 (NWA 15856)

Ouargla, Algeria

Find: 2020

Classification: HED achondrite (Eucrite, polymict)

History: A single piece with heavily weathered fusion crust covering 60% of its surface was found by Nomads in the Sahara Desert close to the town of Ouergla, Algeria. It was subsequently purchased by a dealer Nouakchott, Mauritania in April 2021 and sold to Sean Mahoney.

Physical characteristics: One single piece weighing 530 g, with heavily weathered fusion crust over 60% of its surface, and desert varnish over the remaining part.

Petrography: (D. Sheikh, Cascadia) Sample is a breccia comprised of predominantly mm-sized angular to sub-rounded cumulate and basaltic eucrite clasts, and minor diogenite clasts (also mm-sized, <10 vol. %) set within a fragmental, fine-grained matrix. Accessory phases identified include SiO2-rich glass, troilite, and Fe-Ni metal.

Geochemistry: Eucrite Clasts [Low-Ca Pyroxene (Fs47.3±2.7Wo3.5±0.8, range Fs40.3-50.7Wo2.5-4.9, Fe/Mn=30±3, n=12), Pigeonite (Fs43.1±3.2Wo13.5±6.5, range Fs38.5-47.9Wo5.8-24.1, Fe/Mn=32±4, n=11), High-Ca Pyroxene (Fs27.0±2.6Wo36.4±4.3, range Fs24.5-29.9Wo30.6-40.9, Fe/Mn=29±6, n=4), Calcic Plagioclase (An86.8±1.7, range An84.0-89.9, n=19)]; Diogenite Clasts [Low-Ca Pyroxene (Fs32.2±0.9Wo2.6±0.1, range Fs31.5-32.9Wo2.6-2.7, Fe/Mn=33±4, n=2)].

Classification: HED Achondrite (Eucrite, polymict).

Specimens: 20.8 g at Cascadia, main mass with Sean Mahoney.

Data from:
  Table 0
  Line 0:
Origin or pseudonym:Nearby to Ouergla
Mass (g):530
Shock stage:moderate
Weathering grade:moderate
Ferrosilite (mol%):47.3±2.7, 43.1±3.2, 27.0±2.6, 32.2±0.9
Wollastonite (mol%):3.5±0.8, 13.5±6.5, 36.4±4.3, 2.6±0.1
Classifier:D. Sheikh, Cascadia
Type spec mass (g):20.8
Type spec location:Cascadia
Main mass:Sean Mahoney
Comments:CML 1630; OSM007; 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 46 approved meteorites from Ouargla, Algeria (plus 1 unapproved name)
     This is 1 of 1315 approved meteorites from Algeria (plus 30 unapproved names) (plus 4 impact craters)

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