Northwest Africa 11604 (NWA 11604)

Algeria

Purchased: 2016 May 1

Classification: HED achondrite (Howardite)

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

Physical characteristics: The medium gray matrix contains a variety of clasts and the fusion crust is not found in this small sample.

Petrography (L. Huang, B. Miao, H. Chen, GUT): Breccia containing a variety of basaltic eucrite lithologies (~55 vol%) and cumulate eucrite lithologies (~30 vol%), with ~15 vol% diogenite lithologies. Basaltic eucrite lithologies mostly have a fine-grained recrystallized or subophitic texture. The texture of cumulate eucrite lithologies is equigranular with subequal amounts of pyroxene and plagioclase grains. Diogenite lithologies mostly contain orthopyroxene. Accessories are silica, ilmenite, chromite, troilite.

Geochemistry (L. Huang, B. Miao, H. Chen, GUT): Bulk pyroxene: Fe/Mn=30.9; Orthopyroxene of diogenite lithologies: median compositions are Mg#=66.9, Fs_32.3Wo_2.3 (n=10). Low-Ca pyroxene of cumulate eucrite lithologies: median compositions are Mg#=54.3, Fs_44.8Wo_2.0 (n=12). Low-Ca pyroxene of basaltic eucrite lithologies: median compositions are Mg#=38.8, Fs_59.5Wo_2.6 (n=10). High-Ca pyroxene of basaltic eucrite lithologies: median compositions are Mg#=51.6, Fs_28.1Wo_41.8 (n=8). Plagioclase: median An_92.5Or_0.3 (n=8).

Classification: Polymict brecciated howardite

Specimens: 1.2 g and polished thin section are deposited in GUT