Northwest Africa 11105 (NWA 11105)

Algeria

Purchased: April 2016

Classification: Iron meteorite (IAB-MG)

History: Two specimens weighing 378 g and 176 g reportedly found in Algeria.

Physical characteristics: The main masses have elongate, flattened shapes with dark brown to light red-brown exterior surfaces. Terrestrial alteration, including oxidation and presence of caliche are evident covering approximately half of each rock.

Petrography: Polished and etched surfaces show an irregular pattern with rare kamacite laths approximately 1 mm across. Veins of iron oxides extend into the interior. No fusion crust or heat-affected zone was observed.

Geochemistry: ICP-MS data, using sample of North Chile (Filomena) as standard (C. Herd and G. Chen UAb): Ni = 6.4, Co = 0.45 (both wt%); Ir = 2.4, Ga = 66, Ge = 331, W = 2.3, Re = 0.2, Os = 0.4, Cu = 183, Ru = 13.0, Pd = 1.8, Pt = 17.3 (all μg/g).

Classification: (C. Herd, UAb): IAB-MG, although concentrations of W and Pt seem to be anomalously high.

Specimens: Type specimen consisting of a 12.1 g representative slice and a 14.5 g end piece at UAb. Main mass with Kuntz.