Northwest Africa 11592 (NWA 11592)

Algeria

Purchased: 2016 May 1

Classification: HED achondrite (Eucrite)

History: Purchased by Miao Bing-an in 2016 in Morocco.

Physical characteristics: This achondrite is covered on two surfaces with a shiny black fusion crust (~2 mm thick). The interior appears massive and is a smokey gray color. Many cracks penetrate the interior of this meteorite. A minute amount of white deposit lines one crack. Dimensions: 2.5 × 2.0 × 4.5 cm.

Petrography (L. Huang, B. Miao, H. Chen, GUT): This meteorite is an unbrecciated pigeonite-plagioclase rock with medium grain size. Textures are ophitic with medium-grained (~0.3-0.8 mm) pyroxenes and granular to lath-shaped plagioclase grains. Pyroxenes generally contain pigeonite with augite lamellae. It also contains a shock vein (width ~4 mm) and a vein associated with formation of medium-grained ferroan olivine (~50-250 μm) and sometimes fine-grained ilmenite, chromite and rare very fine-grained phosphate (apatite and merrillite). Accessories are silica, ilmenite, chromite, troilite.

Geochemistry (L. Huang, B. Miao, H. Chen, GUT): Bulk pyroxene: Fe/Mn=31.7; low-Ca pyroxene: median compositions are Mg#=37.5; Fs_59.9Wo_4.2 (n=25). Augite lamellae: median compositions are Mg#=50.1, Fs_29.9Wo_40.9 (n=12). Plagioclase: An_87.2-90.0Or_0.5-0.9, median An_88.1Or_0.7 (n=8).

Classification: Basaltic unbrecciated eucrite

Specimens: 4.2 g and polished thin section are deposited in GUT