Meteoritical Bulletin: Entry for Northwest Africa 15644

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Northwest Africa 15644

Basic information

Name: Northwest Africa 15644
This is an OFFICIAL meteorite name.
Abbreviation: NWA 15644
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass: 1.9 g

Classification
history:

Meteoritical Bulletin:	MB 112	(2023)	Lunar (gabbro)
Recommended:			Lunar (gabbro) [explanation]

This is 1 of 13 approved meteorites classified as Lunar (gabbro). [show all]
Search for other: Lunar meteorites

Comments:

Approved 11 Feb 2023

Writeup

help

Writeup from MB 112:

Northwest Africa 15644 (NWA 15644)

(Northwest Africa)

Purchased: 2022

Classification: Lunar meteorite (gabbro)

History: Acquired online by Daniel Sheikh.

Physical characteristics: Single stone with partial fusion crust. Dark shock veins are visible running through the interior.

Petrography: (D. Sheikh, Cascadia) Sample is a coarse-grained igneous rock displaying a predominant cumulate texture comprised of ~mm-sized subhedral olivine, pigeonite, subcalcic augite, low-Ca pyroxene, and calcic plagioglase. Accessory phases include K-spar, baddeleyite, fluorapatite, ilmenite, merrillite, pentlandite, Ti-bearing chromite, troilite, and taenite.

Geochemistry: Olivine (Fa_31.6±0.3, range Fa_31.0-32.4, Fe/Mn=87±6, n=23), Low-Ca Pyroxene (Fs_26.6±0.5Wo_3.9±0.2, range Fs_26.2-27.0Wo_3.7-4.1, Fe/Mn=55±3, n=2), Pigeonite (Fs_25.2±0.8Wo_10.6±2.3, range Fs_23.4-26.6Wo_7.9-16.5, Fe/Mn=50±4, n=14), High-Ca Pyroxene (Fs_15.3±1.4Wo_36.5±2.2, range Fs_13.0-18.7Wo_32.4-39.9, Fe/Mn=43±6, n=16), Calcic Plagioclase (An_91.2±1.7Or_1.3±0.3, range An_87.5-93.1Or_0.7-1.9, n=17). (M. Neuman, WUSL) Bulk rock chemistry (in wt. %): SiO₂=43.9±0.2, Al₂O₃=5.1±0.1, FeO=19.2±0.8, MgO=24.7±0.1, CaO=5.1±0.1, Na₂O=0.1±0.1, K₂O=0.1±0.1, TiO₂=0.4±0.1, Cr₂O₃=0.4±0.1, MnO=0.2±0.1; (in ppm) Sm=4.4±0.1, Sc=24.5±0.7, Th=1.6±0.1, U=0.5±0.1.

Classification: Lunar (gabbro). Sample is texturally and compositionally (both in mineral chemistry and bulk rock chemistry) identical to NWA 2977, NWA 6950, and other members of the NWA 773 clan, indicating this sample is likely paired alongside those.

Specimens: 0.71 g at Cascadia, main mass with Daniel Sheikh.

Data from:
  MB112
  Table 0
  Line 0:

Place of purchase:	online
Date:	P 2022
Mass (g):	1.9
Pieces:	1
Class:	Lunar (gabbro)
Shock stage:	moderate
Weathering grade:	low
Fayalite (mol%):	31.6±0.3
Ferrosilite (mol%):	26.6±0.5, 25.2±0.8, 15.3±1.4
Wollastonite (mol%):	3.9±0.2, 10.6±2.3, 36.5±2.2
Classifier:	D. Sheikh, Cascadia
Type spec mass (g):	0.71
Type spec location:	Cascadia
Main mass:	Daniel Sheikh
Comments:	CML 1535; submitted by Daniel Sheikh

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)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 112, in preparation (2023)

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Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9699 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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Revision
history:

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