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Northwest Africa 15312
Basic information Name: Northwest Africa 15312
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15312
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 1021 g
Meteoritical Bulletin:  MB 111  (2023)  Lunar (melt breccia)
Recommended:  Lunar (melt breccia)    [explanation]

This is 1 of 28 approved meteorites classified as Lunar (melt breccia).   [show all]
Search for other: Lunar meteorites
Comments: Approved 12 Nov 2022
Writeup from MB 111:

Northwest Africa 15312 (NWA 15312)

(Northwest Africa)

Find: Dec 2021

Classification: Lunar meteorite (melt breccia)

History: Edwin Thompson gave a 32.6 g slice to Cascadia for classification with the following information: He purchased the meteorite from a broker in Mauritania, who said that it was found in December 2021 near Agouémit, Mauritania; no geographic coordinates were obtained. The main mass has since been transferred to Paul Stahura.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): In thin section, the sample is comprised of clasts ranging from single grain fragments <10 μm across to rock fragments up to 4 mm in length. Melt zones between clasts are dominantly feldspathic and cryptocrystalline, although an elongate stringer of brown glassy material (~3.5 × 0.7 mm) abuts one of the larger clasts. Fractures filled with a combination of feldspar and calcite cut across the section.

Geochemistry: Individual grains across the entire section were analyzed, along with two of the larger clasts. Excluding the larger clasts, olivine: Fa28.4±5.2, Fe/Mn = 86.7±6.6, N=31; low-Ca pyroxene: Fs21.0±5.0Wo3.7±0.7, Fe/Mn = 50.1±4.6, N=27; pigeonite: Fs30.5±6.0Wo8.3±3.0, N=9; high-Ca pyroxene: Fs15.1±5.1Wo36.2±9.5, N=15; plagioclase feldspar: Ab4.1±1.8Or0.5±0.1An95.4±1.8, N=17. Clast 4 (~2.2 × 1.7 mm) consists of roughly 60% feldspar (Ab19.4±7.6Or1.0±0.3An80.1±8.0, N=11), 35% pigeonite (Fs24.2±2.6Wo11.5±7.4, N=2) and high-Ca pyroxene (Fs17.4±0.6Wo31.5±2.7, N=2), and 5% olivine (Fa32.5±0.7, N=6). Clast 5 (~2.5 × 1.4 mm) consists of about 50% feldspar (Ab7.7±1.7Or0.6±0.3An91.7±1.9, N=5), 30% olivine (Fa22.3±0.6, N=4), and 20% low-Ca pyroxene (Fs18.8±0.4Wo2.8±0.4, N=4) and high-Ca pyroxene (Fs8.6±0.5Wo43.5±0.8, N=3).

Classification: This meteorite is best described as a lunar feldspathic clast-rich melt breccia base on texture and chemistry.

Specimens: Cascadia holds 26.8 g in one piece, as well as a polished thin section and material in an epoxy butt; Paul Stahura holds the main mass.

Data from:
  Table 0
  Line 0:
Date:Dec 2021
Mass (g):1021
Class:Lunar (melt breccia)
Fayalite (mol%):28.4±5.2 (N=31)
Ferrosilite (mol%):21.0±5.0 (N=27)
Wollastonite (mol%):3.7±0.7 (N=27)
Classifier:M. Hutson, A. Ruzicka and D. Sheikh, Cascadia
Type spec mass (g):32.6
Type spec location:Cascadia
Main mass:Paul Stahura
Comments:Lab number CML 1518; submitted by Melinda Hutson
   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)
Thompson: Edwin Thompson, 5150 Dawn St., Lake Oswego, OR 97035, United States (private address)
References: Published in Gattacceca J., McCubbin F. M., Grossman J. N., Schrader D. L., Chabot N. L., D’Orazio M., Goodrich C., Greshake A., Gross J., Joy K. H., Komatsu M. and Miao B. (2023) The Meteoritical Bulletin, No. 111. Meteoritics & Planetary Science 58, 901–904. ?
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Public domain photographs:
Melinda Hutson   

     This is 1 of 9776 approved meteorites from (Northwest Africa) (plus 1862 unapproved names)

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