Lunar Meteorite: Northwest Africa 16520

Sawn faces of a 1.8-g (L) and 4.4-g (R) piece of Northwest Africa 16520. Many of the dark clasts appear to be vesicular suggesting that they are impact-melt breccias. Photo credits: Jason Whitcomb
Two views of a 5.2-g piece of NWA 16520. Photo credits: Jason Whitcomb

from The Meteoritical Bulletin, No. 113

Northwest Africa 16520 (NWA 16520)

(Northwestern Africa)
Purchased: 2022 August
Mass: 875 g (numerous pieces)

Lunar meteorite (fragmental breccia)

History: Jason Whitcomb purchased many stones from an Algerian dealer. Place and date of find, unknown.

Petrography: (C. Herd and I. Malakhova, UAb) Cut surfaces show light grey and dark clasts set in a medium grey matrix, with a light red-brown rind. Optical and microprobe examination of a polished thin section reveals a fragmental breccia with a variety of clasts up to 5 mm across. Dark, rounded clasts up to 2.6 mm across consist of plagioclase, clinopyroxene and olivine. Angular to sub-angular mineral or lithic clasts <0.5 to 5 mm across predominate. Small (<50 μm) Fe-Ni metal grains are present throughout. Mineral grains show subgrain boundaries suggesting re-equilibration. Terrestrial alteration consists of primarily brownish-red caliche on exterior surfaces.

Geochemistry: (C. Herd, A. Locock, and I. Malakhova, UAb) Data obtained by EMP examination of carbon-coated thin section: pigeonite Fs29±4 Wo10±3, Fe/Mn=52±4 (n=8); augite Fs20±2Wo36±1, Fe/Mn=50±4 (n=3); olivine Fa30±5 (Fa18-42, Fe/Mn=94±7, n=16); plagioclase An96.8±1.2 (n=14).

Classification: Lunar (fragmental breccia).

Specimens: Type specimen of 21.8 g at UAb, main mass with Jason Whitcomb.

Randy Says…

I have not studied Northwest Africa 16520.

More Information

Meteoritical Bulletin Database

NWA 16520

Lunar Meteorites
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