Plateau du Tademait 008 Mars Shergottite (olivine-phyric basalt) #2 – 0,2 g

Plateau du Tademait 008        28°55’03.8″N, 0°59’05.6″E

Adrar, Algeria

Purchased: 2022

Classification: Martian meteorite (Shergottite)

History: Purchased from Algerian dealer Ali Mftah Mftah by Mark Lyon in 2022.

Physical characteristics: Single stone with patches of black fusion crust, sandblasted surfaces show exposed olivine phenocrysts. A polished slice reveals numerous pale green olivine phenocrysts up to ~1 cm in diameter that poikilitically enclose smaller pyroxene grains. The groundmass consists of dark gray pyroxene grains up to 500 μm and smaller olivine grains.

Petrography: (C. Agee, UNM) This meteorite has the approximate modal abundances: 50% clinopyroxene, 25% olivine, 10% maskelynite, with accessory ilmenite, chromite, Ti-Cr spinel, and pyrite. Clinopyroxene shows a tightly bound, continuous calcium enrichment trend. Olivine phenocrysts show a narrow compositional range from low Ca-pyroxene to pigeonite to subcalcic augite. Maskelynite is usually observed occupying pyroxene and olivine grain boundary pockets. Small vesicles are scattered throughout.

Geochemistry: (M. Spilde, UNM) Olivine Fa_40.4±0.9, Fe/Mn=50±2, CaO=0.25±0.05, (wt%), n=6; clinopyroxene Fs_26.3±4.6Wo_17.6±9.2, Fe/Mn=29±2, n=12; maskelynite An_51.0±3.2Ab_47.2±3.4Or_1.8±0.5, n=7.

Classification: Martian shergottite (olivine-phyric basalt).

Specimens: 45 g on deposit at UNM, Mark Lyon holds the main mass