|
The Table (British Columbia)
The Table, sometimes called Table Mountain, is a high flow-dominated andesite tuya located south of Garibaldi Lake, northeast of Cheekye and north of Mount Garibaldi, British Columbia, Canada. It rises over above the surface of Garibaldi Lake, which lies less than to the north. The Table is almost impossible to climb because sections of the volcano have collapsed, creating steep and exceptionally rotten rock walls on all sides. Geology The Table is part of the Garibaldi Lake volcanic field, a volcanic field that includes a group of nine small andesitic stratovolcanoes and basaltic andesite vents formed during the early Holocene. This in turn is part of the Garibaldi Volcanic Belt and of the Cascade Volcanoes, Cascade Volcanic Arc that run from southwestern British Columbia to northern California caused by subduction of the Juan de Fuca Plate and Explorer Plate under the North American Plate at the Cascadia subduction zone. Canadian geologist Bill Mathews proposed in 1951 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garibaldi Ranges
The Garibaldi Ranges are the next-to-southwesternmost subdivision of the Pacific Ranges of the Coast Mountains; only the North Shore Mountains are farther southwest. They lie between the valley formed by the pass between the Cheakamus River and Green River on the west (the location of the Resort Municipality of Whistler) and the valley of the Lillooet River on the east, and extend south into Maple Ridge, an eastern suburb of Vancouver, and the northern District of Mission. To their south are the North Shore Mountains overlooking Vancouver while to their southeast are the Douglas Ranges. They take their name indirectly from Mount Garibaldi on the western side of the range, which is the namesake of Garibaldi Provincial Park. Their southern end between the upper Stave River and Pitt Lake is north of the municipality of Maple Ridge, and forms Golden Ears Provincial Park (which was originally part of Garibaldi Park). Their most famous mountain, The Black Tusk, is not among the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Field
A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes such as cinder cones. Lava flows may also occur. They may occur as a monogenetic volcanic field or a polygenetic volcanic field. Description Alexander von Humboldt observed in 1823 that geologically young volcanoes are not distributed uniformly across the Earth's surface, but tend to be clustered into specific regions. Young volcanoes are rarely found within cratons, but are characteristic of subduction zones, rift zones, or in ocean basins. Intraplate volcanoes are clustered along hotspot traces. Within regions of volcanic activity, volcanic fields are clusters of volcanoes that share a common magma source. Scoria cones are particularly prone to cluster into volcanic fields, which are typically in diameter and consist of several tens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wells Gray-Clearwater Volcanic Field
The Wells Gray-Clearwater volcanic field, also called the Clearwater Cone Group, is a potentially active monogenetic volcanic field in east-central British Columbia, Canada, located approximately north of Kamloops. It is situated in the Cariboo Mountains of the Columbia Mountains and on the Quesnel and Shuswap Highlands. As a monogenetic volcanic field, it is a place with numerous small basaltic volcanoes and extensive lava flows. Most of the Wells Gray-Clearwater volcanic field is encompassed within a large wilderness park called Wells Gray Provincial Park. This park was established in 1939 to protect Helmcken Falls and the unique features of the Clearwater River drainage basin, including this volcanic field. Five roads enter the park and provide views of some of the field's volcanic features. Short hikes lead to several other volcanic features, but some areas are accessible only by aircraft. Geology Pleistocene epoch Based on radiocarbon and potassium-argon dating, volcan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bill Mathews
William Henry Mathews (1919–2003) was a Canadian geologist, volcanologist, engineer, and professor. He is considered a pioneer in the study of subglacial eruptions and volcano-ice interactions in North America. Many of his publications continue to be regarded as classics in their field. Biography Bill Mathews was born in Vancouver, British Columbia in 1919. His mother and a brother died when he was two; his father, Vancouver pioneer Thomas Mathews, died when he was 13. Mathews attended King George Secondary School before entering the University of British Columbia in 1935, earning a Bachelor of Applied Science in geological engineering in 1940, followed by a Master of Applied Science with a major in petrology and a minor in physics in 1941. During college, he served as a student assistant for the Geological Survey of Canada from 1938 to 1941, and was also an instructor in the mountain infantry school of the Alpine Club of Canada, training personnel for the Canadian armed forc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascadia Subduction Zone
The Cascadia subduction zone is a convergent plate boundary that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American Plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia. The Explorer, Juan de Fuca, and Gorda plates are some of the remnants of the vast ancient Farallon Plate which is now mostly subducted under the North American Plate. The North American Plate itself is moving slowly in a generally southwest direction, sliding over the smaller plates as well as the huge oceanic Pacific Plate (which is moving in a northwest direction) in other locations such as the San Andreas Fault in central and southern Califo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific Plate (which borders the plate to the west). It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust. The interior of the main continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of crustal material called terranes, which are accreted to the craton by tectonic actions over a long span of time. It is thought that much of North America west of the Rocky Mountains is composed of such terranes. Boundaries The southern boundary with the Cocos Plate to the west and the Caribbean Plate to the east is a transform fault, represented by the Swan Islands Transform Fault unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explorer Plate
The Explorer Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Vancouver Island, Canada, which is partially subducted under the North American Plate. Along with the Juan de Fuca Plate and Gorda Plate, the Explorer Plate is a remnant of the ancient Farallon Plate, which has been subducted under the North American Plate. The Explorer Plate separated from the Juan de Fuca Plate roughly 4 million years ago. In its smoother, southern half, the average depth of the Explorer plate is roughly and rises up in its northern half to a highly variable basin between and in depth. Boundaries The eastern boundary of the Explorer Plate is being subducted under the North American Plate. The southern boundary is a collection of transform faults, the Sovanco Fracture Zone, separating the Explorer Plate from the Pacific Plate. To the southeast is another transform boundary, the Nootka Fault, which separates the Explorer Plate from the Juan de Fuca Plate and for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territories of the United States by population, most populous U.S. state and the List of U.S. states and territories by area, 3rd largest by area. It is also the most populated Administrative division, subnational entity in North America and the 34th most populous in the world. The Greater Los Angeles area and the San Francisco Bay Area are the nation's second and fifth most populous Statistical area (United States), urban regions respectively, with the former having more than 18.7million residents and the latter having over 9.6million. Sacramento, California, Sacramento is the state's capital, while Los Angeles is the List of largest California cities by population, most populous city in the state and the List of United States cities by population, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
