Answer:
The formation of granite
The uplift of the sierra
Erosion by glaciers
The erosion by streams
Explanation:
The Yosemite Valley mountains consist of plutonic granites that were formed in the Cretaceous Period. The oldest rocks are at least 100 million years old, the youngest around 90 million years old. The valley was shaped over the last 30 million years during several ice ages, whose glaciers carved the valley. Except for Half Dome and the summit of El Capitan, all formations in the area were repeatedly covered by ice. After some of these ice ages, a lake formed in the valley in which sediments were deposited. After the last glaciation, which was relatively minor, the terminal moraine that dammed the lake was at the foot of El Capitan. This lake silted up due to sediments and thus formed today's relatively flat valley floor. Up to 600 meters thick sediment deposits can be found near Glacier Point, which were created by at least six lake formations.
