1. Heat: This can come from various sources like the Earth's internal heat, magma intrusions, or even friction from tectonic plate movement. The heat causes the existing minerals within the rock to recrystallize and potentially change their chemical composition.
2. Pressure: This can be caused by the weight of overlying rocks, tectonic forces, or even the pressure of fluids circulating through the rock. The pressure can cause the minerals to align in a particular direction, leading to a change in the rock's texture.
While heat and pressure are the primary forces, other factors can also influence metamorphism, including:
* Fluids: Water, carbon dioxide, and other fluids can interact with the minerals in the rock, causing chemical changes.
* Time: Metamorphic processes can take a long time, allowing for significant changes in the rock's composition and texture.
