Yosemite National Park geologist Greg Stock and USGS civil engineer Brian Collins download data from instruments measuring how much granitic exfoliation sheets move from daily temperature variations as a precursor to rock fall.
How did Half Dome, the massive rock monument in Yosemite National Park, acquire its unique shape?
At the head of the valley in Yosemite National Park - as if on a pedestal - stands Half Dome. It is smoothly rounded on three sides and a sheer vertical face on the fourth. Half Dome, which stands nearly 8,800 feet (2,682 meters) above sea level, is composed of granodiorite, and is the remains of a magma chamber that cooled slowly and crystallized thousands of feet beneath the Earth's surface. The solidified magma chamber - called a pluton - was then exposed by uplift and erosion of the overlying rock. As the overlying rock eroded, the confining pressure on the pluton was removed and a type of weathering called exfoliation slowly created the more rounded appearance of the dome. At the same time, weathering along vertical joints created the steep northwest face. Later glaciation continued the process by undercutting and plucking rock from the already steep face. The processes of weathering continues to this day as shown by the many rock falls which occur within Yosemite Valley.
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Related
Where can I find information about the geology and natural history of National Parks?
Our National Parks are the showcases of our nation's geological heritage. The National Park Service has websites for most individual parks that include information about their geology and natural history. A source of information from the USGS is our Geology and Ecology of National Parks website. The website has listings for regions of the country; selected parks are listed within each region...
What are igneous rocks?
Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies. Intrusive Igneous Rocks: Intrusive, or plutonic, igneous rock forms...
Is glacier ice a type of rock?
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2 O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is...
Are today's glaciers leftovers from the Pleistocene ice age?
Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and related data suggest that all of southern Greenland and...
What is a landslide and what causes one?
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of "mass wasting," which denotes any down-slope movement of soil and rock under the direct influence of gravity. The term "landslide" encompasses five modes of slope movement: falls, topples, slides, spreads, and flows. These are further subdivided by the type of geologic material...
What is the difference between a rock and a mineral?
A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties. Common minerals include quartz, feldspar, mica, amphibole, olivine, and calcite. A rock is an aggregate of one or more minerals, or a body of undifferentiated mineral matter. Common rocks include granite, basalt...
Yosemite National Park geologist Greg Stock and USGS civil engineer Brian Collins download data from instruments measuring how much granitic exfoliation sheets move from daily temperature variations as a precursor to rock fall.
In this image, a manzanita shrub may be seen with Half Dome behind it. Manzanitas are evergreen shrubs with orange or red bark.
In this image, a manzanita shrub may be seen with Half Dome behind it. Manzanitas are evergreen shrubs with orange or red bark.
In this panorama, Yosemite Falls may be seen on the left and Half Dome on the right. Yosemite Falls is the tallest known waterfall in North America, with a total plunge of 2,425 ft (739 m). Half Dome is a granite dome, part of the Sierra Nevada batholith.
In this panorama, Yosemite Falls may be seen on the left and Half Dome on the right. Yosemite Falls is the tallest known waterfall in North America, with a total plunge of 2,425 ft (739 m). Half Dome is a granite dome, part of the Sierra Nevada batholith.
In this image, Half Dome may be seen from the base of Cathedral Spires. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, Half Dome may be seen from the base of Cathedral Spires. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in detail rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in detail rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in panorama rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in panorama rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, all three sections of Yosemite Falls can be seen. Yosemite Falls is the highest measured waterfall in North America at 2,425 ft (739 m) in height. Yosemite Falls is one of the most famous waterfalls within Yosemite National Park.
In this image, all three sections of Yosemite Falls can be seen. Yosemite Falls is the highest measured waterfall in North America at 2,425 ft (739 m) in height. Yosemite Falls is one of the most famous waterfalls within Yosemite National Park.
Rock strength properties of granitic rocks in Yosemite Valley, Yosemite National Park, California
Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California
The geologic story of Yosemite National Park
Geologic history of the Yosemite Valley
Related
Where can I find information about the geology and natural history of National Parks?
Our National Parks are the showcases of our nation's geological heritage. The National Park Service has websites for most individual parks that include information about their geology and natural history. A source of information from the USGS is our Geology and Ecology of National Parks website. The website has listings for regions of the country; selected parks are listed within each region...
What are igneous rocks?
Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies. Intrusive Igneous Rocks: Intrusive, or plutonic, igneous rock forms...
Is glacier ice a type of rock?
Glacier ice, like limestone (for example), is a type of rock. Glacier ice is actually a mono-mineralic rock (a rock made of only one mineral, like limestone which is composed of the mineral calcite). The mineral ice is the crystalline form of water (H 2 O). Most glacier ice forms through the metamorphism of tens of thousands of individual snowflakes into crystals of glacier ice. Each snowflake is...
Are today's glaciers leftovers from the Pleistocene ice age?
Yes and no. It depends on which glaciers you are considering. Parts of the Antarctic Continent have had continuous glacier cover for perhaps as long as 20 million years. Other areas, such as valley glaciers of the Antarctic Peninsula and glaciers of the Transantarctic Mountains may date from the early Pleistocene. For Greenland, ice cores and related data suggest that all of southern Greenland and...
What is a landslide and what causes one?
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of "mass wasting," which denotes any down-slope movement of soil and rock under the direct influence of gravity. The term "landslide" encompasses five modes of slope movement: falls, topples, slides, spreads, and flows. These are further subdivided by the type of geologic material...
What is the difference between a rock and a mineral?
A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties. Common minerals include quartz, feldspar, mica, amphibole, olivine, and calcite. A rock is an aggregate of one or more minerals, or a body of undifferentiated mineral matter. Common rocks include granite, basalt...
Yosemite National Park geologist Greg Stock and USGS civil engineer Brian Collins download data from instruments measuring how much granitic exfoliation sheets move from daily temperature variations as a precursor to rock fall.
Yosemite National Park geologist Greg Stock and USGS civil engineer Brian Collins download data from instruments measuring how much granitic exfoliation sheets move from daily temperature variations as a precursor to rock fall.
In this image, a manzanita shrub may be seen with Half Dome behind it. Manzanitas are evergreen shrubs with orange or red bark.
In this image, a manzanita shrub may be seen with Half Dome behind it. Manzanitas are evergreen shrubs with orange or red bark.
In this panorama, Yosemite Falls may be seen on the left and Half Dome on the right. Yosemite Falls is the tallest known waterfall in North America, with a total plunge of 2,425 ft (739 m). Half Dome is a granite dome, part of the Sierra Nevada batholith.
In this panorama, Yosemite Falls may be seen on the left and Half Dome on the right. Yosemite Falls is the tallest known waterfall in North America, with a total plunge of 2,425 ft (739 m). Half Dome is a granite dome, part of the Sierra Nevada batholith.
In this image, Half Dome may be seen from the base of Cathedral Spires. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, Half Dome may be seen from the base of Cathedral Spires. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in detail rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in detail rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in panorama rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, the Moon may be seen in panorama rising over Half Dome. Half Dome is a granite dome, rising about 4,737 ft (1,444 m) above the surrounding valley. It is part of the Sierra Nevada batholith and is one of Yosemite National Park's most famous features.
In this image, all three sections of Yosemite Falls can be seen. Yosemite Falls is the highest measured waterfall in North America at 2,425 ft (739 m) in height. Yosemite Falls is one of the most famous waterfalls within Yosemite National Park.
In this image, all three sections of Yosemite Falls can be seen. Yosemite Falls is the highest measured waterfall in North America at 2,425 ft (739 m) in height. Yosemite Falls is one of the most famous waterfalls within Yosemite National Park.