Balambala        0°3.555’N, 39°6.45’E

North-Eastern, Kenya

Find: 2018 Jan

Classification: Iron meteorite (IIF)

History: Dhagax Bir is the name attributed to the meteorite by the region’s goat herders; the name means metal stone in the local spoken Somali dialect. According to the local residents the meteorite was in this location for as long as anyone could remember, including a woman 60 years of age who regularly herded goats past this stone since she was 10 years old. In January 2018, a nomad identified the stone as an iron meteorite, and then brought it to a local broker in the nearest city of Garissa. The broker began circulating photos and it was subsequently purchased by Mahamed Nur Ogle and John Higgins.

Physical characteristics: The single, approximately shield-shaped mass is about 33 × 41 cm in width and 10-15 cm thick. It is covered in large (~5 cm-wide) regmaglypts; a few cm-sized spherical holes are also present on one side. Some rust is present on the top surface, but otherwise, there is little evidence of oxidation.

Petrography: (C. Herd and L. Tunney, UAb) Optical investigation of a 4.5 × 6 cm polished and etched end slice reveals cm-scale rounded troilite inclusions, and lath-like (~1 × 8 mm) schreibersite inclusions, both swathed in kamacite. The bulk of the meteorite consists of kamacite spindles in a matrix of taenite. The spindles occur evenly throughout, except for adjacent to inclusions, where ~500 μm-wide spindle-poor regions are surrounded by ~200 μm-wide spindle-rich rings that broadly parallel the outlines of the inclusions. SEM investigation reveals that larger kamacite spindles or groupings of spindles are often cored by 50-100 μm subequant schreibersite crystals. The average kamacite bandwidth is 53±17 μm (n=36). Taenite is zoned to higher Ni adjacent to kamacite spindles. No alteration was observed.

Geochemistry: (C. Herd, L. Tunney, and G. Chen, UAb) ICP-MS data, using sample of North Chile (Filomena) as standard: Ni = 13.0, Co = 0.67 (both wt%); Ir = 5.2, Ge = 223, Ga = 8.1, As = 20.6, W = 0.76, Re = 0.45, Pt = 14.9, Cu = 208, Au = 2.6 (all µg/g).

Classification: Iron, IIF, based on the high Ge/Ga ratio, high Co content, and fit with regression parameters established by Kracher et al. (1980).

Specimens: Type specimen of 261 g at UAb. Main mass with Mahamed Nur Ogle and J. Higgins.