IIICD Iron Meteorites


Description: Most members of the IIICD iron meteorites do belong to the structural classes of fine and finest octahedrites, or ataxites. Several members of group IIICD do also contain abundant silicate inclusions, similar to the inclusions in IAB irons, and there are additional similarities in elemental compositions suggesting a close relationship exists between IIICD and IAB irons. Some researchers even place the IIICD irons into newly designed subclasses of the IAB group.


Formation history & Origin: Perhaps both groups share a common origin on a partially differentiated asteroid, one that is also thought to be the source of a class of rare primitive achondrites - the winonaites. However, the irons of group IIICD display some unique features that clearly distinguish them from the IAB irons and other groups. For example, the presence of the carbide haxonite is quite characteristic for the meteorites of group IIICD, an indication that the IIICD irons might have origined from a separate but similar parent body.


Members: This medium-sized group of iron meteorites comprises 42 members. Renowned IIICD iron meteorites are Carlton, Morasko, the highly silicated Maltahöhe, and - last but not least - the anomalous, troilite-rich Mundrabilla from Australia, one of the largest iron meteorites ever found.

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