Batholith

A batholith is a large mass of intrusive igneous rock exposed over at least 100 square kilometers. Most form through the accumulation of multiple plutons in the crust.

Pluton: A body of intrusive igneous rock formed when magma crystallizes beneath Earth’s surface. Batholiths commonly consist of multiple plutons assembled through successive intrusions.
Intrusive rock: Igneous rock that forms when magma cools and solidifies beneath Earth’s surface. A batholith is a large exposed body of intrusive igneous rock.
Subduction zone: A region where one tectonic plate descends beneath another into the mantle. Many batholiths form above subduction zones as water-rich magmas rise through continental crust.
Granite: A coarse-grained intrusive igneous rock composed chiefly of quartz and feldspar. Many exposed batholiths contain extensive granite plutons.
Idaho Batholith: A large Late Cretaceous to Paleogene composite batholith exposed in central Idaho. Its extensive granitic intrusions provide a prominent example of a continental batholith.
Magma chamber: An underground reservoir or zone where molten rock accumulates within Earth’s crust. Magma supplied to crustal intrusions can collect in chambers before cooling.
Igneous rock: Rock formed when molten material cools and solidifies. Batholiths belong to the igneous rocks formed from magma.
Continental arc: A chain of volcanoes and associated intrusions formed on a continent above a subducting plate. Large batholiths commonly underlie the intrusive roots of continental arcs.
Granodiorite: A coarse-grained intrusive igneous rock containing more plagioclase than potassium feldspar. Granodiorite is a common rock type in continental batholiths.
Peninsular Ranges batholith: A composite batholith extending through southern California and the Baja California peninsula. Its distinct western and eastern rock belts record changing conditions during arc magmatism.

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TonaliteRelated: Tonalite commonly occurs as part of large plutonic complexes and batholiths.