In the formation of metamorphic rocks, what effect do temperature and pressure primarily have?

They erode rocks.
They create layers.
They make rocks smaller.
They change existing minerals.

1 answer

In the formation of metamorphic rocks, temperature and pressure primarily change existing minerals. Metamorphism involves the alteration of the mineral composition and structure of pre-existing rocks (either igneous, sedimentary, or earlier metamorphic rocks) due to increased temperature, pressure, and/or the presence of chemically active fluids. This process can lead to the formation of new minerals and the recrystallization of existing ones.