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Northwest Africa 15628
Basic information Name: Northwest Africa 15628
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15628
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 10.9 g
Classification
  history:
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 288 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 14 Jan 2023
Writeuphelp
Writeup from MB 112:

Northwest Africa 15628 (NWA 15628)

(Northwest Africa)

Purchased: 24 Feb 2022

Classification: Martian meteorite (Shergottite)

History: A single stone was purchased by Melinda Hutson from Mustapha Oulkouch on February 24, 2022 and donated to Cascadia. Mustapha Oulkouch said he purchased this stone along with other material in 2021 from nomads.

Petrography: (G. Anim, D. Sheikh, A. Ruzicka, M. Hutson, Cascadia): The sample has a fine-grained, subophitic texture dominated by subhedral-euhedral pyroxene (Average diameter = 0.5±0.3 mm, Max = 1.3 mm, N = 29) and subhedral-anhedral maskelynite (Average diameter = 0.7±0.3 mm, Max = 1.4 mm, N = 21). Mineral modes are pyroxene = 65% and maskelynite = 35%. Pyroxenes are predominantly pigeonite and augite. Most show complex zonation, and preferential alignment. Maskelynite is smooth, homogeneous, and sometimes contains small pyroxene fragments (0.08 ?- 0.2 mm). Accessory phases include pyrite, phosphates, zircon, titano-magnetite, hedenbergite and Si-rich glass. Shock features include mosaicism in pyroxenes, pervasive fracturing, melt pockets, and veinlets. Schlieren of maskelynite or feldspathic glass and pyroxene dominate shock melts. Vesicles (0.1 - 0.8 mm) are present within most melt pockets. Calcite and iron hydroxide weathering products are present within veins and at the edges of vesicles.

Geochemistry: (D. Sheikh, G. Anim, M. Hutson) Pigeonite (Fs51.1±7.0Wo13.0±1.6, range Fs33.8-61.2Wo9.5-15.8, Fe/Mn = 34±2, n = 20), Augite (Fs27.3±6.4Wo32.3±1.3, range Fs22.5-44.2Wo29.8-33.9, Fe/Mn = 30±4, n = 17), Maskelynite (An51.6±4.6Or2.0±0.7, range An40.9-55.6Or1.1-3.4, n = 15).

Classification: Martian (shergottite). Shock stage of M-S4 based on the prevalence of maskelynite.

Specimens: Cascadia holds 9.2 g in two pieces, as well as a polished thin section and material in a polished butt.

Data from:
  MB112
  Table 0
  Line 0:
Place of purchase:Facebook Messenger
Date:P 24 Feb 2022
Mass (g):10.88
Pieces:1
Class:Martian (shergottite)
Shock stage:M-S4
Weathering grade:low
Ferrosilite (mol%):51.1±7.0; 27.3±6.4
Wollastonite (mol%):13.0±1.6; 32.3±1.3
Classifier:G. Anim, D. Sheikh, A. Ruzicka, and M. Hutson, Cascadia
Type spec mass (g):9.2
Type spec location:Cascadia
Main mass:Cascadia
Comments:Lab number CML 1497; submitted by Melinda Hutson
Institutions
   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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2023)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8904 approved meteorites from (Northwest Africa) (plus 1871 unapproved names)

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