Northwest Africa 13974 (NWA 13974)

(Northwest Africa)

Purchased: 2021

Classification: Lunar meteorite

History: Multiple complete individuals ranging in size from 1 - 800 g were found in the Western Sahara. Adam Aaronson purchased the samples in Temara in 2021

Physical characteristics: Exterior of the 20% of the samples is light orangish-gray in color and shows voids, some of which are circular in profile. The cut face shows the interior is darker grey and shows a brecciated texture. Other samples found on the surface are reported to have a shiny black wind-ablated exterior.

Petrography: Description and classification (A. Love, App) Sample is a complex breccia composed of rounded to irregular-shaped, mm-sized lithic and anhedral mineral clasts surrounded by a melt matrix. Lithic clasts include: anorthosite, norite, troctolite, brecciated and shock melted clasts. Mineral clasts are dominantly anorthite with minor zoned olivine. Matrix areas within the thin section show some regions with flow-textured glass and fine vesicles. Additional minerals are: <1vol% FeNi grains, chromite, ilmenite, sulfide, secondary barite and calcite.

Geochemistry: (A. Love, App) Olivine (Fa_29.1±6.8, Fe/Mn=66-92, n=29); low Ca pyroxene (Fs_21.3±3.2Wo_4.4±0.5, Fe/Mn=49-55, n=7); pigeonite (Fs_24.4±4.0Wo_9.0±3.9, Fe/Mn=48-59, n=13); high Ca Pyroxene (Fs_11.7±2.1Wo_38.6±6.3, Fe/Mn=40-47, n=4); plagioclase (An_97.2±0.7Or_0.1±0.1, n=18).

Classification: lunar (feldspathic melt breccia A-S3, low weathering). Textures and mineral compositions (Fe/Mn ratios for Olivine and pyroxene and An content of plagioclase) indicate sample is a melt breccia of lunar origin.

Specimens: Aaronson holds 7889 g comprising the 800 g main mass and additional samples. David Sherman holds 684 g and J. Sinclair holds an additional 166 g. A 40 g specimen is held at the Moroccan ministry of Mines and Environment in Rabat. A 20.2 g type specimen, a polished mount and thin section are on deposit at App.