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Yellowstone Plateau
The Yellowstone Plateau Volcanic Field, also known as the Yellowstone Supervolcano or the Yellowstone Volcano, is a complex volcano, volcanic plateau and volcanic field located mostly in the western U.S. state of Wyoming but also stretches into Idaho and Montana. It is a popular site for tourists. The plateau developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. The eruption of the > Huckleberry Ridge Tuff about 2 million years ago created the more than long Island Park Caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the wide Henry's Fork Caldera at the western end of the first caldera. Activity subsequently shifted to the present Yellowstone Plateau and culminated 630,000 years ago with the eruption of the > Lava Creek Tuff and the formation of the present caldera. Resurgent doming then occurred at both the NE and SW sides of the caldera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Sheridan
Mount Sheridan el. is a prominent mountain peak overlooking Heart Lake in the Red Mountains of Yellowstone National Park. The peak is named in honor of General Philip H. Sheridan, U.S. Army, one of the early protectors of the park. History Members of the Washburn–Langford–Doane Expedition in 1870 gave this mountain the name of ''Brown Mountain'', while Lt. Gustavus C. Doane, also a member of the expedition named the mountain ''Yellow Mountain.'' In 1871 during the Hayden Geological Survey of 1871 Ferdinand Vandeveer Hayden named the peak ''Red Mountain''. Also in 1871, Captain John W. Barlow, a military member of the Hayden expedition ascended the peak on August 10, 1871 and named it Mount Sheridan to honor the general. Years later the name ''Red Mountain'' was given to the entire range in which Mount Sheridan sits. Mount Sheridan Trail The summit can be reached via the Mount Sheridan Trail which spurs off the Heart Lake Trail at the northwest corner of Heart Lake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western United States
The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the West'' changed. Before about 1800, the crest of the Appalachian Mountains was seen as the western frontier. The frontier moved westward and eventually the lands west of the Mississippi River were considered the West. The U.S. Census Bureau's definition of the 13 westernmost states includes the Rocky Mountains and the Great Basin to the Pacific Coast, and the mid-Pacific islands state, Hawaii. To the east of the Western United States is the Midwestern United States and the Southern United States, with Canada to the north, and Mexico to the south. The West contains several major biomes, including arid and semi-arid plateaus and plains, particularly in the American Southwest; forested mountains, including three major ranges, the Sierra Neva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as MIS 1. It is considered by some to be an interglacial period within the Pleistocene Epoch, called the Flandrian interglacial.Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC The Holocene corresponds with the rapid proliferation, growth and impacts of the human species worldwide, including all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phreatic Eruptions
A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evaporation of water to steam, resulting in an steam explosion, explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens in Washington state, hundreds of steam explosions preceded Mt. St. Helens eruption , the 1980 Plinian eruption of the volcano. A less intense Geothermal (geology), geothermal event may result in a mud volcano. Phreatic eruptions typically include steam and rock fragments; the inclusion of liquid lava is unusual. The temperature of the fragments can range from cold to incandescent. If molten magma is included, volcanologists classify the event as a phreatomagmatic eruption. These eruptions occasionally create broad, low-relief Volcanic crater, craters called ''maars''. Phreatic explosions can be accom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Flows
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or underwater, usually at temperatures from . The volcanic rock resulting from subsequent cooling is also often called ''lava''. A lava flow is an outpouring of lava during an effusive eruption. (An explosive eruption, by contrast, produces a mixture of volcanic ash and other fragments called tephra, not lava flows.) The viscosity of most lava is about that of ketchup, roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word ''lava'' comes from Italian and is probably derived from the Latin word ''labes'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolitic
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent to granite. Rhyolitic magma is extremely viscous, due to its high silica content. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been extensively used for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil amendment. Description Rhyolite is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Creek Tuff
The Lava Creek Tuff is a tuff formation in Wyoming, Montana and Idaho, United States, created during the Lava Creek eruption around 630,000 years ago, which formed the Yellowstone Caldera. The Lava Creek Tuff is distributed in a radial pattern around the caldera and is formed of of ignimbrites. The tuff has been exposed by erosion at Tuff Cliff along the Gibbon River. Lava Creek Tuff ranges in color from light gray to pale red in some locales. Rock texture of the tuff ranges from fine-grained to aphanitic and is densely welded. The maximum thickness of the tuff layer is approximately . See also *Snake River Plain *Island Park Caldera *Henry's Fork Caldera The Henry's Fork Caldera in eastern Idaho is a caldera located in an area known as Island Park, west of Yellowstone National Park. The caldera was formed by an eruption 1.3 million years ago of the Yellowstone hotspot. The eruption distributed a ... References Landforms of Yellowstone National Park Geologic formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry's Fork Caldera
The Henry's Fork Caldera in eastern Idaho is a caldera located in an area known as Island Park, west of Yellowstone National Park. The caldera was formed by an eruption 1.3 million years ago of the Yellowstone hotspot. The eruption distributed at least 280 cubic kilometers of ash known as the Mesa Falls Tuff, covering a region including all of Wyoming and most of Colorado, Nebraska, and Kansas. The Henry's Fork Caldera is nested inside of the Island Park Caldera, and the calderas share a rim on the western side. The earlier Island Park Caldera is much larger and more oval and extends well into Yellowstone Park. Although much smaller than the Island Park Caldera, the Henry's Fork Caldera is still sizeable at long and wide and its curved rim is plainly visible from many locations in the Island Park area. Of the many calderas formed by the Yellowstone hotspot, including the later Yellowstone Caldera, the Henry's Fork Caldera is the only one that is currently clearly visible. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesa Falls
The Mesa Falls Tuff is a tuff formation created by the Mesa Falls eruption that formed the Henry's Fork Caldera that is located in Idaho west of Yellowstone National Park. It is the second most recent caldera forming eruption from the Yellowstone hotspot and ejected of of material. This eruption, 1.3 million years BP, was preceded by the Huckleberry Ridge Tuff and succeeded by the Lava Creek Tuff, both of which were also created by the Yellowstone hotspot. See also *Yellowstone Caldera * Snake River Plain *Island Park, Idaho *Upper Mesa Falls Upper Mesa Falls is a waterfall on the Henrys Fork in the Caribou-Targhee National Forest. Upstream from Lower Mesa Falls, it is roughly away from Ashton, Idaho. Upper Mesa Falls is roughly high and wide. Formation Mesa Falls Tuff, which ... * Lower Mesa Falls References Yellowstone hotspot Volcanism of Idaho Volcanism of Wyoming Geologic formations of Wyoming Geologic formations of Idaho Landforms of Yellowstone Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Island Park Caldera
The Island Park Caldera, in the U.S. states of Idaho and Wyoming, is one of the world's largest calderas, with approximate dimensions of 80 by 65 km. Its ashfall is the source of the Huckleberry Ridge Tuff that is found from southern California to the Mississippi River near St. Louis. This super-eruption of approximately occurred 2.1 Ma (million years ago) and produced 2,500 times as much ash as the 1980 eruption of Mount St. Helens. Island Park Caldera has the smaller and younger Henry's Fork Caldera nested inside it. The caldera clearly visible today is the later Henry's Fork Caldera, which is the source of the Mesa Falls Tuff. It was formed 1.3 Ma in an eruption of more than . The two nested calderas share the same rim on their western sides, but the older Island Park Caldera is much larger and more oval and extends well into Yellowstone National Park.Newhall and Daniel Dzurisin, 1988, "Historical Unrest at Large Calderas of the World", ''U.S. Geological Survey Bullet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huckleberry Ridge Tuff
The Huckleberry Ridge Tuff is a tuff formation created by the Huckleberry Ridge eruption that formed the Island Park Caldera that lies partially in Yellowstone National Park, Wyoming and stretches westward into Idaho into a region known as Island Park. This eruption of of material is thought to be one of the largest known eruptions in the Yellowstone hotspot's history. This eruption, 2.1 million years ago, is the third most recent large caldera-forming eruption from the Yellowstone hotspot. It was followed by the Mesa Falls Tuff and the Lava Creek Tuff eruptions. The eruption likely occurred in 3 phases, separated by decades. See also *Yellowstone Caldera * Snake River Plain *Island Park Caldera *Henry's Fork Caldera The Henry's Fork Caldera in eastern Idaho is a caldera located in an area known as Island Park, west of Yellowstone National Park. The caldera was formed by an eruption 1.3 million years ago of the Yellowstone hotspot. The eruption distributed ... Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
