Dark inclusion
A dark inclusion is a fragment of darker, finer-grained chondritic rock embedded in a CV or other carbonaceous chondrite.
A dark inclusion is a clast that looks darker and more fine-grained than the meteorite around it. They are typical of CV chondrites, including Allende and Vigarano, and range from a few millimetres to several centimetres across.
Most dark inclusions are made of fine olivine-rich material with few or no chondrules, or with chondrules that have been strongly altered. Their origin is debated. Some scientists think they are pieces of the same parent body that were altered by water and then dried by heating before being broken up and mixed back in. Others think they came from a different region or a different body altogether.
Dark inclusions demonstrate that carbonaceous chondrites are often breccias, mixtures of fragments with different histories. They remind researchers that a meteorite is not always a single uniform rock and that a cut slice may hold several stories side by side.
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