N'Goureyma meteorite, Djenné Cercle, Mopti Region, Malii

Regional Level Types
N'Goureyma meteorite	Meteorite Fall Location
Djenné Cercle	Cercle
Mopti Region	Region
Mali	Country

N'Goureyma, Anomalous Iron (I-ung).
Fall, 15 June 1900; 37.5 kg

The N'Goureyma iron meteorite (~9.4 % Ni) was observed to fall and was afterwards recovered from a deep hole. The original mass was an unusual oriented, shield-shape with a concave front and somewhat broader back. Within a few weeks it was acquired by H. Minod and subsequently sectioned and sold to various parties. The principal constituents are the expected kamacite, taenite, troilite, and (very sparse) schreibersite found in most meteoritic irons. However, N'Goureyma is — both crystallographically and geochemically — a very unusual iron meteorite. The kamacite is present as polycrystalline aggregates separated by taenite ribbons, but there is no Widmanstätten pattern. Troilite is both abundant and ubiquitous as very fine-grained inclusions. Minor constituents — chromite, schreibersite, and isocubanite — are each reported by at least two observers. Even though the meteorite is a witnessed fall, there is little crust with weather-produced limonite found in both crust and cracks — cracks which may already have been present when the meteorite struck the earth.

The N'Goureyma meteoroid was apparently structurally weakened by preterrestrial impact, the sustained pressures of its fiery atmospheric passage, and some unusually rapid tropical weathering before the meteorite pieces were eventually stored in relatively dry and quiet museums. N'Goureyma is one of only 4 witnessed I-ung falls. The 117 ungrouped irons constitute ~11% of the classified iron meteorites — presumably, the remnants of various asteroidal cores. Every meteorite is a somewhat enigmatic stranger to our planet — but the entangled history of this particular witnessed fall is perhaps more puzzling than most.

The largest masses are held at Heidelberg (4 kg) and Paris [Museum National d'Histoire Naturelle] (1.5 kg).

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