NWA 11017 Achondrite Diogenite Part Slice weighing 1.74g

Northwest Africa 11017 (NWA 11017)

(Northwest Africa)

Purchased: 2016 Jun

Classification: HED achondrite (Diogenite, polymict)

History: Purchased by Fabien Kuntz in June 2016 from a dealer in Zagora, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Breccia composed of >90 vol.% angular grains of diogenitic orthopyroxene (of several different compositions), sparse grains of olivine, augite, chromite and calcic plagioclase, and rare lithic clasts in a finer-grained matrix of the same minerals plus troilite and stained Ni-free metal. Lithic clasts include sparse polycrystalline diogenite, quench-textured eucrite (containing elongate pigeonite crystals within glassy mesostasis) and a fine grained breccia lithology. Minor secondary barite occurs in the matrix and some calcite veinlets are present.

Geochemistry: Orthopyroxene (Fs_13.8Wo_4.2; Fs_17.9Wo_0.7; Fs _25.8Wo_2.5; FeO/MnO = 25-30), augite (Fs_16.4-18.7Wo_42.6-42.3, FeO/MnO = 23-25), pigeonite in quenched eucrite clast (Fs_41.7Wo_6.7, FeO/MnO = 31). Magnetic susceptibility log χ (× 10^-9 m³/kg) = 3.10.

Classification: Diogenite (polymict breccia). The wide range of Fe/Mg in diogenitic orthopyroxene is an unusual feature.

Specimens: 23.69 g including one polished thin section at PSF; remainder with Kuntz.