Geology. Change in the structural, mineralogical, or chemical characteristics of rocks; (later) spec. that produced by chemical and physical…

metamorphism affecting rocks over an extensive area as a result of the large-scale action of heat and pressure.

the transformation of rock as a result of an igneous intrusion.

Metamorphism occurring at high temperatures and pressures at great depths in the earth's crust.

metamorphism produced by the action of heat.

Geol. Metamorphism below oxidation level resulting in the formation of complex minerals from simpler ones.

Alteration of rocks (usually at or near the earth's surface) characterized by the formation of chemically simpler minerals from more complex ones.

metamorphism caused by pressure.