What is catazone in geology ?

Catazone - Metamorphism

Metamorphic facies diagram
The term catazone (or katazone) designates a region subjected to strong metamorphism, in temperature (more than 700°C) and in pressure, inducing the crystallization of potassium feldspar, calcium plagioclases, sillimanite, garnet, etc...

In terms of metamorphic gradient, it is the facies of granulites and eclogites, with frequent presence of sillimanite and biotite gneisses. Catazone is the final stage of metamorphism before fusion or anatexis.