Plutons are large, igneous rock formations that form beneath the Earth's surface when magma cools and solidifies slowly. They can vary in size from small bodies to massive structures, often taking millions of years to form. Common types of plutons include batholiths, stocks, and sills, each defined by their size and shape. These geological features are important for understanding the Earth's crust and the processes that shape it. Plutons can be exposed at the surface through erosion, revealing valuable information about the history of volcanic activity and the movement of tectonic plates in the region.