List of Slides for Yosemite NP

• Half Dome, Yosemite's most famous landmark, draws the immediate attention of anyone entering Yosemite Valley from the west.
• Half Dome formed by two processes related to joints (cracks) in the rock: the vertical face developed when rock between closely-spaced joints broke away, and the rounded side developed through exfoliation.
• Exfoliation occurs when deeply-buried rock is exposed at the earth's surface by erosion. Removal of the overlying layers causes the rock to expand slightly, cracking in sheets parallel to the surface.
• Here exfoliation affects a granite outcrop.
• North Dome, Half Dome, and others in the park have thus formed as concentric layers split away from the exposed granite surface.
• Yosemite lies within the largest mountain range in the United States - the Sierra Nevada. This range consists of an enormous granitic batholith, shown in red on the map, as well as many smaller igneous plutons.
• The rock of the batholith is exposed throughout the high country of Yosemite.
• John Muir called the Sierra Nevada "the Range of Light" because of the widespread outcrops of light-colored granite. Tenaya Lake is visible near the right edge of this picture.
• El Capitan, in Yosemite Valley, is a massive outcrop of granitic rock nearly free of joints, and thus highly resistant to weathering.
• Much of the spectacular scenery in Yosemite Valley and throughout the park is due to the effects of Pleistocene glacial erosion. Here, the valley of the Tuolomne River shows the transition from V-shaped (typical of rivers) and U-shaped (carved by a glacier).
• The lower part of the Tuolomne valley was dammed in 1923, over the protests of naturalists, including John Muir.
• The valley is now filled by Hetch Hetchy Reservoir, which provides water for San Francisco.
• Hetch Hetchy Valley once contained waterfalls similar to Yosemite Falls in Yosemite Valley.
• Yosemite Falls is one of the highest waterfalls in the United States, descending 2425 feet in two falls and an intervening cascade.
• Several of the waterfalls, including Yosemite Falls, issue from hanging valleys, whose mouths lie high above the main valley floor.
• A large glacier in the main valley could erode much deeper than smaller glaciers in the tributary glaciers. This left the side valleys hanging at a higher elevation, so that today's streams leap down in torrents such as Bridalveil Falls.
• Vernal Falls descends a giant "staircase" excavated by the glacier.
• Here the ice plucked away pieces of fractured rock to produce a high ledge, over which the Merced River drops.
• More evidence of the former glaciers lies scattered across the park in the form of erratics - huge boulders carried by the ice and dropped when it melted.
• Stream erosion and mass wasting continue to shape the Yosemite landscape. For example, landslides across Tenaya Creek formed Mirror Lake.
• Giant sequoia trees, intolerant of glacial conditions, returned to the park some 3000-4000 years ago, after the ice disappeared.