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San Juan Volcanic Field
The San Juan volcanic field is part of the San Juan Mountains in southwestern Colorado. It consists mainly of volcanic rocks that form the largest remnant of a major composite volcanic field that covered most of the southern Rocky Mountains in the Middle Tertiary geologic time.Steven, Thomas A.; Lipman, Peter W. (1976)"Calderas of the San Juan Volcanic Field, Southwestern Colorado" ''U.S. Geological Survey Professional Papers''. Washington, DC: U.S. Government Printing Office. 958: 1–35. Retrieved 2012-05-16. There are approximately fifteen calderas known in the San Juan Volcanic Fields; however, it is possible that there are two or even three more in the region. The region began with many composite volcanoes that became active between 35 and 40 million years ago, with peak activity in the time period around 35-30 million years ago. Around this time the activity began to include explosive ash-flow eruptions. Many of these volcanoes experienced caldera collapse, resulting in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado
Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the eighth most extensive and 21st most populous U.S. state. The 2020 United States census enumerated the population of Colorado at 5,773,714, an increase of 14.80% since the 2010 United States census. The region has been inhabited by Native Americans and their ancestors for at least 13,500 years and possibly much longer. The eastern edge of the Rocky Mountains was a major migration route for early peoples who spread throughout the Americas. "''Colorado''" is the Spanish adjective meaning "ruddy", the color of the Fountain Formation outcroppings found up and down the Front Range of the Rocky Mountains. The Territory of Colorado was organized on February 28, 1861, and on August 1, 1876, U.S. President Ulyss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bimodal Volcanism
Bimodal volcanism is the eruption of both mafic and felsic lavas from a single volcanic centre with little or no lavas of intermediate composition. This type of volcanism is normally associated with areas of extensional tectonics, particularly rifts. Occurrence Most occurrences of bimodal volcanism are associated with thinning of the crust and the presence of such rocks in metamorphic sequences has been used to provide evidence for past rifting events. Most examples come from areas of active continental rifting such as the Basin and Range Province. Bimodal volcanism has also been described from areas of transtension, the early phases of back-arc basin formation and in the products of both continental and oceanic hotspots (e.g. Yellowstone, Anahim and the Canary Islands). Mechanism of formation Bimodal volcanism is normally explained as a result of partial melting of the crust, creating granitic magma Magma () is the molten or semi-molten natural material from which all i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of The Rocky Mountains
The geology of the Rocky Mountains is that of a discontinuous series of mountain ranges with distinct geological origins. Collectively these make up the Rocky Mountains, a mountain system that stretches from Northern British Columbia through central New Mexico and which is part of the great mountain system known as the North American Cordillera. The rocky cores of the mountain ranges are, in most places, formed of pieces of continental crust that are over one billion years old. In the south, an older mountain range was formed 300 million years ago, then eroded away. The rocks of that older range were reformed into the Rocky Mountains. The Rocky Mountains took shape during an intense period of plate tectonic activity that resulted in much of the rugged landscape of the western North America. The Laramide orogeny, about 80–55 million years ago, was the last of the three episodes and was responsible for raising the Rocky Mountains. Subsequent erosion by glaciers has created the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Volcanoes
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 plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Juan Mountains (Colorado)
The San Juan Mountains is a high and rugged mountain range in the Rocky Mountains in southwestern Colorado and northwestern New Mexico. The area is highly mineralized (the Colorado Mineral Belt) and figured in the gold and silver mining industry of early Colorado. Major towns, all old mining camps, include Creede, Lake City, Silverton, Ouray, and Telluride. Large scale mining has ended in the region, although independent prospectors still work claims throughout the range. The last large scale mines were the Sunnyside Mine near Silverton, which operated until late in the 20th century and the Idarado Mine on Red Mountain Pass that closed down in the 1970s. Famous old San Juan mines include the Camp Bird and Smuggler Union mines, both located between Telluride and Ouray. The Summitville mine was the scene of a major environmental disaster in the 1990s when the liner of a cyanide-laced tailing pond began leaking heavily. Summitville is in the Summitville caldera, one of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Fields Of Colorado
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 plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Large Volume Volcanic Eruptions In The Basin And Range Province
Large volume volcanic eruptions in the Basin and Range Province include Basin and Range eruptions in California, Idaho, Colorado, New Mexico, Texas, Arizona, Nevada, Wyoming and Oregon, as well as those of the Long Valley Caldera geological province and the Yellowstone hotspot. Volcanic fields Some of the volcanic fields within the Basin and Range Province: Northwestern Nevada, the Modoc Plateau, Central Nevada, the Great Basin, Southwestern Nevada, the Mojave Desert, and the Long Valley Caldera region. Named ones include: Coso Volcanic Field, Mono Lake Volcanic Field, Marysvale Volcanic Field, San Juan volcanic field, Indian Peak, Central Colorado volcanic field, Jemez volcanic lineament, Mogollon-Datil volcanic field, Santa Rosa-Calico, and Boot Heel volcanic field. Geological features Many geological features in Western United States have a Northeastern orientation, the North American craton motion has the same orientation as well. For example: the Trans-Challis fault zone, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Canyon Tuff
The Fish Canyon Tuff is the large volcanic ash flow or ignimbrite deposit resulting from one of the largest known Explosive eruption, explosive eruptions on Earth, estimated at . (see List of largest volcanic eruptions). The Fish Canyon Tuff eruption was centred at the La Garita Caldera in southwest Colorado; the caldera itself would have formed by collapse, as a result of the eruption. Studies of the tuff show that it all belongs to one eruption due to its uniform bulk-chemical composition (SiO2=bulk 67.5–68.5% (dacite), matrix 75–76% (rhyolite) and consistent phenocryst content (35–50%) and mineralogical composition (plagioclase, sanidine, quartz, biotite, hornblende, sphene, apatite, zircon, Fe-Ti oxides are the primary phenocrysts). This tuff and eruption is part of the larger San Juan volcanic field and the Mid-Tertiary_ignimbrite_flare-up, Oligocene Southern Rocky Mountain ignimbrite flare-up. The Fish Canyon Tuff eruption occurred around 28 Million years ago. Sanidine c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Garita Caldera
La Garita Caldera is a large caldera in the San Juan volcanic field in the San Juan Mountains near the town of Creede in southwestern Colorado, United States. It is west of La Garita, Colorado. The eruption that created the La Garita Caldera is among the largest known volcanic eruptions in Earth's history, as well as being one of the most powerful known supervolcanic events. Date The La Garita Caldera is one of a number of calderas that formed during a massive ignimbrite flare-up in Colorado, Utah and Nevada from 40–18 million years ago, and was the site of massive eruptions about , during the Oligocene Epoch. Area devastated The area devastated by the La Garita eruption is thought to have covered a significant portion of what is now Colorado. The deposit, known as the Fish Canyon Tuff, covered at least . Its average thickness is . The eruption might have formed a large-area ash-fall, but none has yet been identified. Size of eruption The scale of La Garita volcanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographic Coordinates
The geographic coordinate system (GCS) is a spherical or ellipsoidal coordinate system for measuring and communicating positions directly on the Earth as latitude and longitude. It is the simplest, oldest and most widely used of the various spatial reference systems that are in use, and forms the basis for most others. Although latitude and longitude form a coordinate tuple like a cartesian coordinate system, the geographic coordinate system is not cartesian because the measurements are angles and are not on a planar surface. A full GCS specification, such as those listed in the EPSG and ISO 19111 standards, also includes a choice of geodetic datum (including an Earth ellipsoid), as different datums will yield different latitude and longitude values for the same location. History The invention of a geographic coordinate system is generally credited to Eratosthenes of Cyrene, who composed his now-lost ''Geography'' at the Library of Alexandria in the 3rd century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado State Route 114, Near Cochetopa Dome, Colorado (14223891743)
Colorado (, other variants) is a state in the Mountain West The Mountain West Conference (MW) is one of the collegiate athletic conferences affiliated with the National Collegiate Athletic Association (NCAA) Division I Football Bowl Subdivision (FBS) (formerly I-A). The MW officially began operations o ... subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the List of U.S. states and territories by area, eighth most extensive and List of U.S. states and territories by population, 21st most populous U.S. state. The 2020 United States Census, 2020 United States census enumerated the population of Colorado at 5,773,714, an increase of 14.80% since the 2010 United States Census, 2010 United States census. The region has been inhabited by Indigenous peoples of the Americas, Native Americans and their Paleo-Indians, ancest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
