Northwest Africa 11577 (NWA 11577)

Morocco

Purchased: 2017 Jan

Classification: Iron meteorite (IAB-sHL)

History: Reportedly found in Algeria by nomads in December 2016, subsequently sold to a Moroccan merchant in Ouarzazate, from whom it was purchased by J. Shea.

Physical characteristics: The main mass consists of two tabular specimens approximately 1 cm thick, both having dark brown exteriors.

Petrography: (C. Herd, UAb) SEM investigation of a ~2 × 3 cm polished surface reveals a well-developed Widmanstatten pattern consistent with a finest octahedrite (0.025±0.005 mm; n=16). Some areas of kamacite are coarser, and some kamacite has been replaced by terrestrial oxidation.

Geochemistry: ICP-MS data, using sample of North Chile (Filomena) as standard (C. Herd and G. Chen UAb): Ni = 12.5, Co = 0.55 (both wt%); Ir = 0.12, Ga = 17, Ge = 38, As = 24, W = 0.38, Re = 0.01, Os = 0.22, Cu = 276, Au = 2.7 (all μg/g).

Classification: (C. Herd, UAb): IAB iron, sHL subgroup according to Wasson and Kallemeyn (2002).

Specimens: Type specimen consisting of two representative slices (16.6 and 2.1 g) at UAb. Main mass with Shea.