Intrusive igneous rock body's are called

It is called intrusion. It is an igneous rock body which is formed from a crystallized magma under the surface of the Earth. From deep within, magma slowly pushes up. It pushes up into any space or any cracks it can find. Pushing existing country rocks out of the way sometimes, can happen millions of years. As the rocks cool down into solid, the other parts of the magma crystallize and form into minerals. Mountain ranges like Sierra Nevada in California is an example of an intrusion.