What is the definition of a batholith?

A batholith is defined as a large, complex mass of intrusive igneous rock that has solidified from magma beneath the Earth's surface. It is characterized by its considerable size, often extending over hundreds of square kilometers, and typically composed of granitic rock.

Batholiths are formed when magma cools and crystallizes slowly under the Earth's crust, which allows for large crystals to form, resulting in a coarse-grained texture. This slow cooling and the associated formation process distinguish batholiths from smaller plutonic bodies like stocks or dikes.

In geological features, batholiths often serve as the foundational rock layer for mountain ranges and can affect the surrounding geology significantly. The scale and complexity of these bodies mean they can also exhibit a variety of mineral compositions depending on the source of the magma and the surrounding rock that it interacts with during formation. Thus, understanding batholiths is essential for interpreting the geological history and mineral resources of a region.