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26-634: The Skwawka River is a medium-sized river in the Pacific Ranges of the Coast Mountains in British Columbia , Canada , flowing southeast 20 kilometers (12 mi) into the head of Queens Reach, which is the uppermost end of Jervis Inlet . The pass at the head of the river, which connects to the head of the Little Toba River , is the prominence col for Mount Alfred , which lies just west of

52-436: A cinder cone eruption, the magma has lost most of its gas content. This gas-depleted magma does not fountain but oozes quietly into the crater or beneath the base of the cone as lava. Lava rarely issues from the top (except as a fountain) because the loose, uncemented cinders are too weak to support the pressure exerted by molten rock as it rises toward the surface through the central vent. Because it contains so few gas bubbles,

78-409: A cinder cone is usually basaltic to andesitic in composition. It is often glassy and contains numerous gas bubbles "frozen" into place as magma exploded into the air and then cooled quickly. Lava fragments larger than 64 mm across, known as volcanic bombs , are also a common product of cinder cone eruptions. The growth of a cinder cone may be divided into four stages. In the first stage,

104-409: A low-rimmed scoria ring forms around the erupting event. During the second stage, the rim is built up and a talus slope begins to form outside the rim. The third stage is characterized by slumping and blasts that destroy the original rim, while the fourth stage is characterized by the buildup of talus beyond the zone where cinder falls to the surface (the ballistic zone ). During the waning stage of

130-576: A new vent. Eruptions continued for nine years, built the cone to a height of 424 meters (1,391 ft), and produced lava flows that covered 25 km (9.7 sq mi). The Earth's most historically active cinder cone is Cerro Negro in Nicaragua. It is part of a group of four young cinder cones NW of Las Pilas volcano. Since its initial eruption in 1850, it has erupted more than 20 times, most recently in 1995 and 1999. Satellite images suggest that cinder cones occur on other terrestrial bodies in

156-469: A series of coast ranges and exotic mountains. A high rate of sedimentation from the outflow of the three major rivers ( Fraser River , Columbia River , and Klamath River ) which cross the Cascade Range contributes to further obscuring the presence of a trench. However, in common with most other subduction zones, the outer margin is slowly being compressed, similar to a giant spring . When the stored energy

182-680: Is Hunlen Falls , among the highest in Canada , located in Tweedsmuir South Provincial Park . Other than logging and various hydroelectric developments, and a large ski resort at Whistler , most of the land in the range is completely undeveloped. Historically, in the southern part of the range, mining was important at various times in the Lillooet, Bridge River and Squamish areas, and large pulp and paper mills at Powell River, Port Mellon and Woodfibre. The largest hydroelectric development in

208-430: Is a stub . You can help Misplaced Pages by expanding it . Pacific Ranges The Pacific Ranges include four of the five major coastal icecaps in the southern Coast Mountains . These are the largest temperate-latitude icecaps in the world and fuel a number of very major rivers (by volume, not length). One of these contains Mount Waddington , the highest summit entirely within British Columbia . Also within this region

234-441: Is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent . The pyroclastic fragments are formed by explosive eruptions or lava fountains from a single, typically cylindrical, vent. As the gas-charged lava is blown violently into the air, it breaks into small fragments that solidify and fall as either cinders, clinkers, or scoria around

260-511: Is incomplete Some Protected areas, recreation areas and other non-park preservation areas are not listed. Many relatively unknown rivers of considerable size along the coastal flank of the range are not listed, partly because they are largely unknown and also very difficult to access. For a full listing of rivers in the Pacific Ranges, see List of rivers of the Pacific Ranges . Cinder cone A cinder cone (or scoria cone )

286-535: Is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large earthquakes , such as the 8.7–9.2 M w   Cascadia earthquake of 1700 . Many smaller ranges and subranges are not listed at present. (Other than the Waddington Range these are also considered to be " ranges " but are listed separately here because of their unique character). List

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312-458: The Coalstoun Lakes volcanic field , and some cinder cones on Mauna Kea are monogenetic cinder cones. However, not all cinder cones are monogenetic, with some ancient cinder cones showing intervals of soil formation between flows that indicate that eruptions were separated by thousands to tens of thousands of years. Monogenetic cones likely form when the rate of magma supply to a volcanic field

338-693: The Garibaldi Volcanic Belt was from the Mount Meager massif 2,350 BP , which is Canada's most recent major catastrophic eruption. The Garibaldi Volcanic Belt contains two extra volcanic fields, the Franklin Glacier Complex and the Silverthrone Caldera , which lie 140 and 190 km northwest of the main volcanic belt. The Cascadia subduction zone is a 680 mi (1,094 km) long fault , running 50 mi (80 km) off

364-783: The Pacific Ranges is the Bridge River Power Project , though smaller hydro plants are on the Stave River-Alouette Lake system in Mission and Maple Ridge, the Daisy Lake-Squamish River division of the Cheakamus Powerhouse, and another power dam and power plant at Clowhom . Although the range was extensively surveyed for possible rail routes, only that of the Pacific Great Eastern (now part of CN)

390-782: The Pacific Ranges, which is a volcanic belt formed by the subduction of the Juan de Fuca Plate (a remnant of the much larger Farallon Plate ) under the North American Plate along the Cascadia subduction zone . The belt is the northern extension of the Cascade Volcanic Arc in the United States (which includes the volcanoes Mount St. Helens and Mount Baker ) and contains the most explosive young volcanoes in Canada. The eruption styles in

416-450: The belt range from effusive to explosive , with compositions from basalt to rhyolite . Morphologically, centers include calderas , cinder cones , stratovolcanoes and small isolated lava masses. Due to repeated continental and alpine glaciations, many of the volcanic deposits in the belt reflect complex interactions between magma composition, topography, and changing ice configurations. The most recent major catastrophic eruption in

442-599: The dispersion of ejected scoria particles. For example, cinder cones on Mars seem to be more than two times wider than terrestrial analogues as lower atmospheric pressure and gravity enable wider dispersion of ejected particles over a larger area. Therefore, it seems that erupted amount of material is not sufficient on Mars for the flank slopes to attain the angle of repose and Martian cinder cones seem to be ruled mainly by ballistic distribution and not by material redistribution on flanks as typical on Earth. Cinder cones often are highly symmetric, but strong prevailing winds at

468-510: The flanks of Mauna Kea , a shield volcano located on the island of Hawaii . Such cinder cones likely represent the final stages of activity of a mafic volcano. However, most volcanic cones formed in Hawaiian-type eruptions are spatter cones rather than cinder cones, due to the fluid nature of the lava. The most famous cinder cone, Paricutin , grew out of a corn field in Mexico in 1943 from

494-446: The molten lava is denser than the bubble-rich cinders. Thus, it often burrows out along the bottom of the cinder cone, lifting the less dense cinders like corks on water, and advances outward, creating a lava flow around the cone's base. When the eruption ends, a symmetrical cone of cinders sits at the center of a surrounding pad of lava. If the crater is fully breached, the remaining walls form an amphitheater or horseshoe shape around

520-474: The river's mouth and is the highest summit between Jervis and Toba Inlets . Above the river's lower reaches, on the east flank of Mount Alfred, is 700 meters (2,300 ft) Alfred Creek Falls , one of North America's highest. 50°13′00″N 123°59′00″W  /  50.21667°N 123.98333°W  / 50.21667; -123.98333 This article about a river in the Coast of British Columbia , Canada

546-677: The solar system. On Mars, they have been reported on the flanks of Pavonis Mons in Tharsis , in the region of Hydraotes Chaos on the bottom of the Coprates Chasma , or in the volcanic field Ulysses Colles . It is also suggested that domical structures in Marius Hills (on the Moon) might represent lunar cinder cones. The size and shape of cinder cones depend on environmental properties as different gravity and/or atmospheric pressure might change

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572-465: The time of eruption can cause a greater accumulation of cinder on the downwind side of the vent. Some cinder cones are monogenetic , forming from a single short eruptive episode that produces a very small volume of lava. The eruption typically last just weeks or months, but can occasionally last fifteen years or longer. Parícutin in Mexico, Diamond Head , Koko Head , Punchbowl Crater , Mt Le Brun from

598-460: The vent to form a cone that often is symmetrical; with slopes between 30 and 40°; and a nearly circular ground plan. Most cinder cones have a bowl-shaped crater at the summit. Cinder cones range in size from tens to hundreds of meters tall. They are composed of loose pyroclastic material ( cinder or scoria ), which distinguishes them from spatter cones , which are composed of agglomerated volcanic bombs . The pyroclastic material making up

624-443: The vent. Basaltic cinder cones are the most characteristic type of volcano associated with intraplate volcanism . They are particularly common in association with alkaline magmatism , in which the erupted lava is enriched in sodium and potassium oxides . Cinder cones are also commonly found on the flanks of shield volcanoes , stratovolcanoes , and calderas . For example, geologists have identified nearly 100 cinder cones on

650-484: The west-coast of the Pacific Northwest from northern California to Vancouver Island . The plates move at a relative rate of over 0.4 inches (10 mm) per year at a somewhat oblique angle to the subduction zone. Unlike most subduction zones worldwide, there is no oceanic trench present along the continental margin in Cascadia . Instead, terranes and the accretionary wedge have been uplifted to form

676-584: Was eventually built; the Homathko River-Bute Inlet route, however, was one of the two main choices in the deliberations of the CPR's routing. The Pacific Ranges are part of the southern portion of the Coast Plutonic Complex and has been characterized by rapid rates of uplift over the past 4 million years, which has led to relatively high rates of erosion . The Garibaldi Volcanic Belt is within

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