You searched for: “katamorphism
katamorphism, zone of katamorphism
1. Metamorphism that occurs at or near the earth's surface where it breaks down complex minerals into simpler ones.
2. At or near the earth's surface or the outer zone of the solid earth in which the alterations of rocks result in the production of simple compounds from more complex ones.

It is subdivided into an "outer belt of weathering" and an "inner belt of cementation".