The Sierra Nevada Batholith is a large batholith

Batholith

A batholith is a large emplacement of igneous intrusive rock that forms from cooled magma deep in the Earth's crust...

 which forms the core of the Sierra Nevada mountain range in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, USA, exposed at the surface as granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

.

The batholith is composed of many individual masses of rock called plutons, which formed deep underground during separate episodes of magma

Magma

Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...

 intrusion

Intrusion

An intrusion is liquid rock that forms under Earth's surface. Magma from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years. As the rock slowly...

, millions of years before the Sierra itself first began to rise. The extremely hot, more buoyant

Buoyancy

In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

 plutons, also called plutonic diapirs, intruded through denser, native country rock

Country rock (geology)

Country rock is a geological term meaning the rock native to an area. It is similar and in many cases interchangeable with the terms basement and wall rocks....

 and sediments, never reaching the surface.