Sahara 03505

Sahara

Find: 2003

Iron (ungrouped)

History: A single mass was found in the desert in 2003. The find location is undisclosed.

Physical characteristics: The meteorite weighs 65 g and has no fusion crust.

Petrography: (L. Folco, MNA-SI; M. D’Orazio, DST-PI; P. Rochette, CEREGE) The meteorite consists of cellular/ dendritic Fe,Ni-rich metal crystals set in a matrix dominated by troilite. Fe,Ni-rich metal and troilite occur approximately in a 1:1 volumetric ratio. The primary dendrite arms are up to >1.6 cm long and about 100 µm wide, while the spacing of the secondary arms, perpendicular to the primary, is ~100–150 µm. Abundant spherical droplets (5–100 µm) of anhydrous Fe-, Fe-Na-, and Fe-Mn-Na-K-phosphates are scattered within the troilite. Skeletal crystals of nearly endmember chromite, up to 2.5 mm in maximum length, complete the primary mineral assemblage. Fe,Ni metal is ataxitic and is made of a fine (1–5 µm) aggregate of Ni-rich metal (up to 39.3 wt% Ni), kamacite, and subordinate schreibersite. Veinlets of terrestrial oxidation phases cross-cut the primary minerals and are more abundant toward the external surface.

Geochemistry: Bulk composition: (Analysis by ICP-MS) Co = 4.14, Ni = 90.2 (both mg/g); Cu = 341, Ga = 21.2, Ge = 32.5, Ir = 3.6, Pt = 7.8 (all µg/g).

Classification: Iron (ungrouped). It is troilite-rich and similar in petrography, mineralogy, and bulk chemistry to the Mount Howe (HOW) 88403 ungrouped iron.

Type specimen: A 13 g specimen is on deposit at MNA-SI. Caillou Noir holds the main mass.

A list of all meteorites recognized from countries and regions within Africa is provided in Table 1.