Sierra Nevada batholith

The Sierra Nevada batholith is an extensive assemblage of granitic rocks in California and Nevada, crystallized from magma beneath a Mesozoic volcanic arc along western North America.

Pluton: A body of igneous rock formed when magma crystallizes underground. The batholith consists of many plutons that solidified at depth.
Nevadan orogeny: A Late Jurassic mountain-building episode along western North America. Its deformation and magmatism preceded and accompanied early Sierra Nevada arc development.
Batholith: A large intrusive igneous body exposed over at least 100 square kilometers. The Sierra Nevada body is a named example of this broad intrusive-rock form.
Yosemite Valley: A glacially carved valley in California’s Sierra Nevada, famed for its granite cliffs. Its iconic cliffs expose granitic rocks belonging to the batholith.
Subduction zone: A region where one tectonic plate descends beneath another into the mantle. Subduction supplied water and helped generate the arc magmas that formed its plutons.
Jurassic period: A geologic period spanning about 201 to 145 million years ago. Much of the batholith’s magmatic history began during the Jurassic.
Volcanic arc: A chain of volcanoes formed above a subduction zone. The batholith is the deep, exposed counterpart to an ancient arc’s volcanic system.
Half Dome: A prominent granite peak in Yosemite National Park, California. Its exposed rock is part of the batholith’s Yosemite-area granitic intrusions.
Fractional crystallization: The changing composition of magma as growing crystals are separated from the remaining melt. Crystal separation helped produce the batholith’s varied intrusive rock compositions.
Cretaceous period: A geologic period spanning about 145 to 66 million years ago. A substantial portion of the batholith crystallized during Cretaceous arc activity.

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