The metamorphic rocks are associated with bands of epidiorite which have shared in the folding and metamorphism of the region.
Nor is the metamorphism of the invaded rock limited to simple intrusion.
All of the chemical, mineralogical, and textural changes in rocks above described may be collectively referred to as metamorphism.
A common cause of the metamorphism of rocks is the intrusion into them of igneous rocks.
Often no granite or other intrusive rock is present which may be regarded as the cause of the metamorphism.
This state of things is called general, or normal, metamorphism.
The metamorphism is more striking in the first change than in the second.
How is metamorphism on the large scale supposed to have been induced?
An important result of metamorphism is the production of new minerals in the rocks acted on.
Whether the rocks below the zone of metamorphism are fused or not depends on pressure.
The process by which rocks are changed in composition, texture, or structure by extreme heat and pressure. ◇ In prograde metamorphism metamorphic rocks that were formed under low pressure and temperature conditions undergo a second metamorphic event in which they are exposed to higher pressures and temperatures. ◇ In retrograde metamorphism metamorphic rocks that were formed under high pressure and temperature conditions undergo a second metamorphic event in which they are exposed to lower pressures and temperatures. See more at contact metamorphism, regional metamorphism.