Northwest Africa 13568 (NWA 13568)

Tindouf, Algeria

Purchased: 2020

Classification: Lunar meteorite

History: Many samples, associated with the main mass of 625 g, (total 825 g) were found in the vicinity of Tindouf, Algeria. All material was purchased by Adrián Contreras from a meteorite dealer in the area.

Physical characteristics: Samples are dark in color with light orange patches caliche and have blocky irregular shapes. The cut face shows the interior is a breccia of lithic and mineral clasts set dark gray matrix with regions of small vesicles.

Petrography: Description and classification (A. Love, App) Polymict breccia dominated by angular, irregularly shaped, 1 mm to 3 cm sized mineral, lithic and vitrified clasts set within a melt matrix composed of isotropic to partially devitrified translucent glass and angular mineral fragments. Gabbroic lithic clasts are dominant, fragmental clasts set in opaque glass. Additional minerals are: troilite, FeNi metal.

Geochemistry: (A. Love, App) Olivine, Fa_26.0±7.1 (Fa_18.0-37.0, Fe/Mn=81.5±7.1, n=11); low-Ca pyroxene, Fs_29.4±11.8Wo_3.3±0.8 (Fs_17.1-48.8Wo_2.4-4.8, Fe/Mn=52.9±4.9, n=21); pigeonite, Fs_38.7±6.2Wo_13.8±3.3 (Fs_29.1-45.3Wo_9.7-19.1, Fe/Mn=55.0±3.3, n=9); high-Ca pyroxene, Fs_32.5±7.9Wo_30.1±4.2(Fs_22.3-41.0Wo_21.8-34.2, Fe/Mn=54.7±5.1, n=6); plagioclase, An_97.0±0.6Or_0.0±0.10 (n=9).

Classification: Lunar (feldspathic breccia M-S3, low weathering). Based on textures, melt matrix component and mineral compositions, this sample is a feldspathic breccia.

Specimens: Adrián Contreras holds the 58 2 g main mass. A polished thin section and 2 slices and several fragments weighing 31.26 g are on deposit at App.