Genomict breccia
A genomict breccia contains fragments of the same meteorite group but of different petrologic types or textures.
A genomict breccia sits between monomict and polymict breccias. All its fragments belong to the same meteorite group, but they differ in petrologic type or texture. A typical example is an H chondrite breccia containing clasts of H3, H5 and H6 material side by side.
Genomict breccias are common among ordinary chondrites. They show that the parent asteroid had a range of zones that were heated to different degrees, perhaps an onion-like structure with the most heated material at the centre, and that impacts later dug up and mixed fragments from different depths. Many regolith breccias are genomict.
Recognising a genomict breccia matters for classification. A meteorite may be listed as, for example, H3-6, meaning it contains fragments spanning those types. Measuring each fragment's cooling history helps test whether the parent body stayed intact or was disrupted and reassembled while still warm.
Related terms
Level: Expert Advanced