Sierra Nevada Fault

Around 200 million years ago, the ancient oceanic Farallon plate began to subduct beneath the North American plate. As the Farallon moved eastward, it was overridden by the North American, and the moisture within it was figuratively baked out of the rock before the crust melted into magma. As it began to cool, a large mass of igneous rock was created and is now visible as the granite domes of the Sierra Nevada Batholith.^[2] Batholiths are large masses of igneous rock that form deep below the surface, and they are thought to be the "roots" of subduction-zone volcanoes.^[3] After the below-surface formation of the granite, processes such as uplift and erosion eventually expose it to the surface.

There are several contributors to the uplift of the Sierra Nevada Batholith. Shear forces replace compression as the North American plate begins riding over with the Pacific plate. On the other side of the Sierra Nevada Range, the Basin and Range Province is pulled apart as the force of compression increases.^[4] It is the Farallon plate subsidence which is thought to be the force behind the creation of the Sierra Nevada.