Type Iron Parent body IAB | Class Primitive achondrite | |
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Structural classification Hexahedrites, fine to coarse octahedrites, sometimes ataxites Subgroups sLL
sLM (was IIIC)
sLH (was IIID)
sHL
sHH (includes Gay Gulch trio)
Udei Station grouplet
Pitts grouplet
Algarrabo duo
Mundrabilla duo
Britstown duo
NWA 468 duo
Twin City duo
Solo irons related to IAB Composition Meteoric iron (kamacite & taenite) & silicate inclusions | ||
IAB meteorites are a group of iron meteorites according to their overall composition and a group of primitive achondrites because of silicate inclusions that show a strong affinity to winonaites and chondrites.
Contents
Description
The IAB meteorites are composed of meteoric iron (kamacite and taenite) and silicate inclusions. Structurally they can be hexahedrites, fine to coarse octahedrites, or even ataxites. Most of them are octahedrite with medium to coarse taenite-lamella and distinct Widmanstätten patterning.
The silicate inclusions are composed of low-Ca pyroxene, high-Ca pyroxene, olivine, plagioclase, troilite, graphite, different phosphates, meteoric iron and traces of daubréelite and chromite. This composition is very similar to the composition of winonaites and it is therefore argued that the two groups share the same parent body. There are also similarities with the IIICD meteorites, but it is not yet clear if they are also part of that parent body.
Classification
The IAB group was created from the older IA and IB groups. Some authors also prefer to call it IAB complex.
There are numerous subdivisions of the IAB group:
Parent body
Most scientist believe that the winonaites, and the IAB meteorites share the same parent body. It is not yet fully understood if the IIICD meteorites also belong to that body.