core-and-mantle structure

Deformed crystalline core, usually a single crystal, surrounded by a mantle of fine-grained material of the same mineral. The structure is thought to develop by preferential dynamic re-crystallisation in the outer shell of a deforming large single crystal in response to intracrystalline deformation. Feldspar core-and-mantle structures are common in rocks subject to low to medium-grade deformation

Related terms:

• lower mantle
• upper mantle
• Mantle
• atoll structure
• core sample
• augen
• core intersection
• inner mantle
• outer mantle
• platy quartz