Half Dome is a granite dome in Yosemite National Park, located in northeastern Mariposa County, California, at the eastern end of Yosemite Valley — possibly Yosemite’s most familiar rock formation. The granite crest rises more than 4,737 ft (1,444 m) above the valley floor.
Half Dome from Olmsted Point
The photo above shows famed Half Dome in Yosemite Valley, California as viewed from Olmsted Point, looking west. This massive granite monolith, looming 4,737 ft (1,444 m) above the valley floor, formed approximately 80 million years ago. It’s part of the central Sierra Nevada Range. Intense glacial scouring shaped Yosemite and many other valleys in the Sierra’s during the last 1.5 million years. The fractured rocks visible in the foreground here are granodiorite (granite and diorite), which is similar to granite but contains more plagioclase. Red Fir and Jeffry Pine have been successful at gaining a foothold in this severely scoured landscape. Photo taken in July of 2010. [epod]
Landsat 7 image Brandberg Massif, Namibia
The first effort to protect the area that is now Yosemite National Park was actually done by President Abraham Lincoln (a pretty influential person in American history) who signed a bill to protect parts of Yosemite Valley and the Mariposa grove of Sequoia trees.
John Muir, one of the best known American environmentalists, loved exploring the vast wilderness areas of northern California. The destruction of subalpine meadows around Yosemite Valley lead Muir into a prolonged struggle to protect the area which eventually lead to Yosemite becoming the nation´s second National Park (after Yellowstone) in 1890.
Even though the park was protected by the national government, the city of San Francisco, California had long been planning to dam the Tuolomne River as a source of drinking water and hydroelectric power for the city. Despite another long, political struggle (with Muir again at the forefront), the river was eventually damned. There are still efforts underway today to recover the natural state of the Tuolomne River which runs through the Hetch Hetchy Valley.
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