Batholith -

: Because the magma is trapped underground, it cools very slowly over millions of years, allowing large mineral crystals—often granite —to grow.

A is a massive body of intrusive igneous rock that forms when a large volume of magma cools and solidifies deep beneath the Earth's surface. Derived from the Greek words bathos (depth) and lithos (rock), it literally means "deep stone". These formations are defined by having a surface exposure of at least 100 square kilometers (about 40 square miles). How They Form batholith

: A batholith is rarely one single rock; it is usually a cluster of multiple smaller igneous bodies called plutons that have merged together. : Because the magma is trapped underground, it

: Molten rock (magma) rises from deep within the mantle but fails to erupt as a volcano. These formations are defined by having a surface

: These "deep stones" only become visible at the surface after millions of years of continental uplift and the erosion of the miles of rock once covering them. Famous Examples