linguistic:paraphrasing
Tectonic and volcanic activity

The location of the park was a passive continental margin during the Precambrian and early Paleozoic. Sediment was derived from continental sources and was deposited in shallow water. These rocks became deformed and metamorphosed.

Heat generated from the Farallon Plate subducting below the North American Plate led to the creation of an island arc of volcanoes on the west coast of proto-North America between the late Devonian and Permian periods. Material accreted onto the western edge of North America, and mountains were raised to the east in Nevada.

The first phase of regional plutonism started 210 million years ago in the late Triassic and continued throughout the Jurassic to about 150 million years before present (BP), which led to the creation of the Sierra Nevada Batholith. The resulting rocks were mostly granitic in composition and lay about 6 miles (9.7 km) below the surface. Around the same time, the Nevadan orogeny built the Nevadan mountain range (also called the Ancestral Sierra Nevada) to a height of 15,000 feet (4,600 m).

The second major pluton emplacement phase lasted from about 120 million to 80 million years ago during the Cretaceous. This was part of the Sevier orogeny.

Starting 20 million years ago (in the Cenozoic) and lasting until 5 million years ago, a now-extinct extension of Cascade Range volcanoes erupted, bringing large amounts of igneous material in the area. These igneous deposits blanketed the region north of the Yosemite region. Volcanic activity persisted past 5 million years BP east of the current park borders in the Mono Lake and Long Valley areas.