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Laramide
The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was deep-seated, thick-skinned deformation, with evidence of this orogeny found from Canada to northern Mexico, with the easternmost extent of the mountain-building represented by the Black Hills of South Dakota. The phenomenon is named for the Laramie Mountains of eastern Wyoming. The Laramide orogeny is sometimes confused with the Sevier orogeny, which partially overlapped in time and space. The orogeny is commonly attributed to events off the west coast of North America, where the Kula and Farallon Plates were sliding under the North American plate. Most hypotheses propose th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sevier Orogeny
The Sevier orogeny was a mountain-building event that affected western North America from northern Canada to the north to Mexico to the south. The Sevier orogeny was the result of convergent boundary tectonic activity, and deformation occurred from approximately 160 million years (Ma) ago to around 50 Ma. This orogeny was caused by the subduction of the oceanic Farallon Plate underneath the continental North American Plate. Crustal thickening that led to mountain building was caused by a combination of compressive forces and Thermal conduction, conductive heating initiated by subduction, which led to deformation. The Sevier River area of central Utah is the namesake of this event. Extent The Sevier Fold and Thrust Belt extends from southern California near the Mexican border to Canada. Basin and Range faults cut the older Sevier thrust faults. The Sevier orogeny was preceded by several other mountain-building events including the Nevadan orogeny, the Sonomia Terrane, Sonoman or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat-slab Subduction
Flat slab subduction is characterized by a low subduction angle (<30 degrees to horizontal) beyond the and a resumption of normal subduction far from the . A slab refers to the subducting lower . Although, some would characterize flat slab as any shallowly dipping lower plate as in western |
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in the southwestern United States. Depending on differing definitions between Canada and the U.S., its northern terminus is located either in northern British Columbia's Terminal Range south of the Liard River and east of the Trench, or in the northeastern foothills of the Brooks Range/ British Mountains that face the Beaufort Sea coasts between the Canning River and the Firth River across the Alaska-Yukon border. Its southernmost point is near the Albuquerque area adjacent to the Rio Grande rift and north of the Sandia–Manzano Mountain Range. Being the easternmost portion of the North American Cordillera, the Rockies are distinct from the tectonically younger Cascade Range and Sierra Nevada, which both lie farther to its west. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basin And Range Province
The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins. The physiography of the province is the result of tectonic extension that began around 17 million years ago in the early Miocene epoch. The numerous ranges within the province in the United States are collectively referred to as the "Great Basin Ranges", although many are not actually in the Great Basin. Major ranges include the Snake Range, the Panamint Range, the White Mountains, and the Sandia Mountains. The highest point fully within the province is White Mountain Peak in California, while the lowest point is the Badwater Basin in Death Valley at . The province's climate is arid, with numerous ecoregions. Most North American deserts are located within it. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado Mineral Belt
The Colorado Mineral Belt (CMB) is an area of ore deposits from the La Plata Mountains in Southwestern Colorado to near the middle of the state at Boulder, Colorado and from which over 25 million troy ounces (778 t) of gold were extracted beginning in 1858. The belt is a "northeast-striking zone defined by: a Proterozoic shear zone system (McCoy, 2001); a suite of Laramide-aged plutons and related ore deposits ( Tweto and Sims, 1963); a major gravity low (Isaacson and Smithson, 1976); low- crustal velocities; and high heat flow (Decker et al., 1988)." Mining districts includ *Central City-Idaho Springs district *Leadville mining district, named for Leadville, Colorado * Sneffels-Red Mountain-Telluride district The belt lies within a zone that has been geologically active at intervals beginning from near the time of crustal accretion in central Colorado at least 1.6 billion years ago until the present. Parts of the CMB follow shear zones of Precambrian age and the Paleozoic an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Hills
The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk Peak (formerly known as Harney Peak), which rises to , is the range's highest summit. The Black Hills encompass the Black Hills National Forest. The name of the hills in Lakota is ', meaning “the heart of everything that is." The Black Hills are considered a holy site. The hills are so called because of their dark appearance from a distance, as they are covered in evergreen trees. Native Americans have a long history in the Black Hills and consider it a sacred site. After conquering the Cheyenne in 1776, the Lakota took the territory of the Black Hills, which became central to their culture. In 1868, the U.S. government signed the Fort Laramie Treaty of 1868, establishing the Great Sioux Reservation west of the Missouri River, and exempt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laramie Mountains
The Laramie Mountains are a range of moderately high peaks on the eastern edge of the Rocky Mountains in the U.S states of Wyoming and Colorado. The range is the northernmost extension of the line of the ranges along the eastern side of the Rockies, and in particular of the higher peaks of the Front Range directly to the south. North of the range, the gap between the Laramie range and the Bighorn Mountains provided the route for historical trails, such as the Oregon Trail, the Mormon Trail, and the Pony Express. The Laramie Mountains begin in northern Colorado and extend discontinuously into southeastern Wyoming between Cheyenne and Laramie and northward to Casper. (By some definitions the Laramies are only in Wyoming.) They are named after the Laramie River, which cuts through the range from southwest to northeast and joins the North Platte River east of the range in eastern Wyoming. The mountains in turn give their name to the Laramide orogeny, the uplift of the North American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orogeny
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted to form one or more mountain ranges. This involves a series of geological processes collectively called orogenesis. These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism. Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere ( crust and uppermost mantle). A synorogenic process or event is one that occurs during an orogeny. The word "orogeny" () comes from Ancient Greek (, , + , , ). Although it was used before him, the term was employed by the American geologist G. K. Gilbert in 1890 to describe the process of mountain-building as distinguished f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Zone
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 dens ... [...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] |
Farallon Plate
The Farallon Plate was an ancient oceanic plate. It formed one of the three main plates of Panthalassa, alongside the Phoenix Plate and Izanagi Plate, which were connected by a triple junction. The Farallon Plate began subducting under the west coast of the North American Plate—then located in modern Utah—as Pangaea broke apart and after the formation of the Pacific Plate at the centre of the triple junction during the Early Jurassic. It is named for the Farallon Islands, which are located just west of San Francisco, California. Over time, the central part of the Farallon Plate was completely subducted under the southwestern part of the North American Plate. The remains of the Farallon Plate are the Juan de Fuca, Explorer and Gorda Plates, subducting under the northern part of the North American Plate; the Cocos Plate subducting under Central America; and the Nazca Plate subducting under the South American Plate. The Farallon Plate is also responsible for transporting old i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the west and south by the Pacific Ocean. Because it is on the North American Plate, North American Tectonic Plate, Greenland is included as a part of North America geographically. North America covers an area of about , about 16.5% of Earth's land area and about 4.8% of its total surface. North America is the third-largest continent by area, following Asia and Africa, and the list of continents and continental subregions by population, fourth by population after Asia, Africa, and Europe. In 2013, its population was estimated at nearly 579 million people in List of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's population. In Americas (terminology)#Human ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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