Lunar Meteorite: Northwest Africa 13916

Slices and exterior of Northwest Africa 13916. Photo credits:

from The Meteoritical Bulletin, No. 110

Northwest Africa 13916 (NWA 13916)

Purchased: 2021
Mass: 175.28 g (1 piece)

Classification: Lunar meteorite (frag. breccia)

History: Purchased by Douglas Chenin from a Mauritanian meteorite dealer in 2021.

Physical characteristics: This meteorite is a single stone with a shiny desert-weathered, sandblasted surface that displays some light-colored clasts set in a very dark groundmass.

Petrography: (C. Agee, UNM) Electron microprobe analysis of a polished mount shows this meteorite to be a lunar polymict breccia with at least 9 distinct lithologies set in a fine-grained cataclastic groundmass of plagioclase, pyroxene and olivine fragments. Ubiquitous silica, merrillite, Fe-sulfide, Fe-metal (low Ni), and ilmenite were detected.

Geochemistry: (C. Agee, UNM) Groundmass olivine Fa35.0±7.6, Fe/Mn=97±9, n=12; clinopyroxene Fs29.7±9.6Wo16.2±15.2, Fe/Mn=55±4, n=13; plagioclase An97.2±1.3, n=5. Clast-1 (microgabbro) clinopyroxene Fs30.3±11.6Wo30.5±16.9, Fe/Mn=65±8, n=3; plagioclase An95.0±0.3, n=2. Clast-2 (ferroan anorthosite) olivine Fa44.5, Fe/Mn=96, n=1; clinopyroxene Fs23.3Wo29.8, Fe/Mn=51, n=1; plagioclase An97.0, n=1. Clast-3 (impact quench-crystal melt) olivine Fa44.0, Fe/Mn=125, n=1; clinopyroxene Fs34.1±4.2Wo11.3±4.2, Fe/Mn=53±5, n=2; plagioclase An96.8, n=1. Clast-4 (anorthositic gabbro) clinopyroxene Fs26.1Wo27.9, Fe/Mn=55, n=1; plagioclase An97.5, n=1. Clast-5 (troctolite) olivine Fa35.8±8.1, Fe/Mn=96±4, n=2; plagioclase An97.6±2.8, n=2. Clast-6 (anorthositic troctolite) olivine Fa17.9, Fe/Mn=76, n=1; plagioclase An96.2, n=1. Clast-7 (microgabbro) clinopyroxene Fs24.4Wo23.9, Fe/Mn=58, n=1; plagioclase An97.8, n=1. Clast-8 (olivine microgabbro) olivine Fa40.8, Fe/Mn=111, n=1; clinopyroxene Fs28.2Wo18.3, Fe/Mn=64, n=1; plagioclase An96.0, n=1. Clast-9 (lunar granite) alkali feldspar Or76.3±1.4Ab22.0±1.3An1.7±0.0, n=2; silica polymorph (2.5wt% Al2O3).

Classification: Polymict fragmental lunar breccia.

Specimens: 21.2 g on deposit at UNMDChenin holds the main mass.

Randy Says…

I have not studied NWA 13916. This breccia has a large variety of clasts. It is unusual for a lunar breccia to have linear and parallel fractures like this.

More Information

Meteoritical Bulletin Database

NWA 13916