Yosemite Creek Yosemite Creek Yosemite Creek is a creek of the Sierra Nevada, located in Yosemite National Park, Mariposa County, California. The creek's headwaters are at the Grant Lakes (), and it flows southwest to drop over Yosemite Falls to Yosemite Valley, then flows southeast to its mouth at the Merced River, just southwest of Yosemite Village. () The Merced is a tributary of the San Joaquin River, in the San Joaquin Valley. Today, Yosemite Creek flows over the Yosemite Valley rim to create Upper Yosemite Fall. Before its diversion about 130,000 years ago, Yosemite Creek flowed down an older channel just
Geology of the Yosemite area Geology of the Yosemite area The exposed geology of the Yosemite area includes primarily granitic rocks with some older metamorphic rock. The first rocks were laid down in Precambrian times, when the area around Yosemite National Park was on the edge of a very young North American continent. The sediment that formed the area first settled in the waters of a shallow sea, and compressive forces from a subduction zone in the mid-Paleozoic fused the seabed rocks and sediments, appending them to the continent. Heat generated from the subduction created island arcs of volcanoes that were also thrust into the