IAB Group


IAB Iron Meteorites


Description: Most IAB irons are coarse to medium octahedrites, although other structural classes do occur. The meteorites of this group often contain abundant inclusions of troilite, graphite, and cohenite, and various silicates that are closely related to a group of primitive achondrites, the winonaites.


Formation history & Origin: Recent research suggests that both the winonaites and the IAB iron meteorites originated on the same parent body - a partially differentiated asteroid that was violently disrupted just as it began to form a nickel-iron core and silicate-rich crust. The disrupting impact mixed silicates into molten nickel-iron forming the silicated IAB irons, and mixed olivine-rich residues of partial melts into unmelted silicates, forming the winonaites.


Members: This well represented group contains about 135 members if we exclude all probable pairings. Some IAB irons are downright famous, as for example, the meteorites of Toluca, Campo del Cielo, Odessa, or Canyon Diablo. The latter one created the well-known Meteor Crater in Arizona, USA. Other members are renowned for their abundant, beautiful silicate inclusions, e.g., Caddo County, Landes, and Zagora, just to name a few.

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