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Mount Garfield (San Juan County, Colorado)
Mount Garfield is a mountain summit located in San Juan County, Colorado, United States. It is situated eight miles south of the community of Silverton, in the Weminuche Wilderness, on land managed by San Juan National Forest. It is part of the San Juan Mountains range which is a subset of the Rocky Mountains of North America. Precipitation runoff from the mountain drains into tributaries of the Animas River. The peak can be seen from U.S. Route 550 and the Durango and Silverton Narrow Gauge Railroad. Topographic relief is significant as the west aspect rises over above the river and railway in approximately one mile. It is set six miles west of the Continental Divide, one mile west of Electric Peak, and three miles east-southeast of Snowdon Peak. Climate According to the Köppen climate classification system, Mt. Garfield is located in an alpine subarctic climate zone with very long, cold, snowy winters, and cool to warm summers. Due to its altitude, it receives precip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Juan County, Colorado
San Juan County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 705, making it the least populous county in Colorado. The county seat and the only incorporated municipality in the county is Silverton. The county name is the Spanish language name for " Saint John", the name Spanish explorers gave to a river and the mountain range in the area. With a mean elevation of 11,240 feet (3426 meters), San Juan County is the highest county in the United States. History Long before European settlement, the area was regularly explored by the Anasazi, and later the Utes, who hunted and lived in the San Juans during the summer. There is also speculation that Spanish explorers and fur traders ventured into the area in the 1600s and 1700s. Permanent settlement in the area surrounding present-day San Juan County began in 1860, near the end of the Colorado Gold Rush. These first settlers were a group of prospectors lead by Charles Baker, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Durango And Silverton Narrow Gauge Railroad
The Durango and Silverton Narrow Gauge Railroad, often abbreviated as the D&SNG, is a 3 ft (914 mm) narrow-gauge heritage railroad that operates on of track between Durango and Silverton, in the U.S. state of Colorado. The railway is a federally-designated National Historic Landmark and was also designated by the American Society of Civil Engineers as a National Historic Civil Engineering Landmark in 1968. The route was originally opened in 1882 by the Denver and Rio Grande Western Railroad (D&RGW) to transport silver and gold ore mined from the San Juan Mountains. The line was an extension of the D&RG narrow-gauge line from Antonito, Colorado to Durango. The last train to operate into Durango from the east was on December 6, 1968. The states of New Mexico and Colorado purchased 64 miles of track between Antonito and Chama, New Mexico in 1970, which is operated today as the Cumbres and Toltec Scenic Railroad (C&TSRR). Trackage between Chama and Durango was removed by 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers ( laminae) less than one centimeter in thickness. This property is called '' fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the more narrow sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks into thin layers, often splintery and usually parallel to the otherwise indistinguishable beddin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, W. H. Freeman, 2nd ed, 529 pp. The term ''mudstone'' is also used to describe carbonate rocks (limestone or dolomite) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane, benzene and toluene. Definition There is not a single definition of mudstone that has gained general acceptance,Boggs 2006, p.143 though there is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than . Individual grains this size are too small to be disting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllite
Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily composed of quartz, sericite mica, and chlorite. Phyllite has fine-grained mica flakes, whereas slate has extremely fine mica flakes, and schist has large mica flakes, all mica flakes of which have achieved a preferred orientation. Among foliated metamorphic rocks, it represents a gradation in the degree of metamorphism between slate and schist. The minute crystals of graphite, sericite, or chlorite, or the translucent fine-grained white mica, impart a silky, sometimes golden sheen to the surfaces of cleavage, called "phyllitic luster". The word comes from the Greek ''phyllon'', meaning "leaf". The protolith (or parent rock) for phyllite is shale or pelite, or slate, which in turn came from a shale protolith. Its constituent platy minerals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartzite
Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of hematite. Other colors, such as yellow, green, blue and orange, are due to other minerals. The term ''quartzite'' is also sometimes used for very hard but unmetamorphosed sandstones that are composed of quartz grains thoroughly cemented with additional quartz. Such sedimentary rock has come to be described as orthoquartzite to distinguish it from metamorphic quartzite, which is sometimes called metaquartzite to emphasize its metamorphic origins. Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica conte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncompahgre Formation
The Uncompahgre Formation is a geologic formation in Colorado. Its radiometric age is between 1707 and 1704 Ma, corresponding to the Statherian period. History The formation was first named by Charles Whitman Cross and Ernest Howe in 1905 for exposures around Uncompahgre Gorge near Ouray, Colorado. They grouped it with the Vallecito Conglomerate into the Needle Mountains Group, but this was abandoned by Tweto in 1977. Karl Karlstrom and coinvestigators informally raised the Uncompahgre Formation to group rank in 2017, assigning the Vallecito Conglomerate as a member. Geology The Uncompahgre Formation is a sequence of quartzite and black phyllite some in thickness. It is exposed in a curving belt from the northwestern to northeastern Needle Mountains with outliers near Ouray and Rico, Colorado. It is interpreted as metamorphosed marine and fluvial sandstone, mudstone, and shale. The formation overlies plutons with an age of 1707 Ma and detrital zircon geochronology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Horn
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples of nunataks. Formation Glaciers, typically forming in drainages on the sides of a mountain, develop bowl-shaped basins called cirques (sometimes called ‘corries’ - from Scottish Gaelic ʰəɾə(a bowl) - or s). Cirque glaciers have rotational sliding that abrades the floor of the basin more than walls and that causes the bowl shape to form. As cirques are formed by glaciation in an alpine environment, the headwall and ridges between parallel glaciers called arêtes become more steep and defined. This occurs due to freeze/thaw and mass wasting beneath the ice surface. It is widely held that a common cause for headwall steepening and extension headward is the crevasses known as bergschrund that occur between the moving ice and the he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subarctic Climate
The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, generally at latitudes from 50° to 70°N, poleward of the humid continental climates. Subarctic or boreal climates are the source regions for the cold air that affects temperate latitudes to the south in winter. These climates represent Köppen climate classification ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'', ''Dwd'' and ''Dsd''. Description This type of climate offers some of the most extreme seasonal temperature variations found on the planet: in winter, temperatures can drop to below and in summer, the temperature may exceed . However, the summers are short; no more than three months of the year (but at least one month) must have a 24-hour average temperature of at least to fall into this category of climate, and the coldest month should ave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Köppen Climate Classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger (1894–1981) introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system. The Köppen climate classification divides climates into five main climate groups, with each group being divided based on seasonal precipitation and temperature patterns. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (temperate), ''D'' (continental), and ''E'' (polar). Each group and subgroup is represented by a letter. All climates are assigned a main group (the first letter). All climates except for those in the ''E'' group are assigned a seasonal precipitation subgroup (the second letter). For example, ''Af'' indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowdon Peak
Snowdon Peak is a mountain summit located in San Juan County, Colorado, United States. It is situated seven miles south of the community of Silverton, in the Weminuche Wilderness, on land managed by San Juan National Forest. It is part of the San Juan Mountains range which is a subset of the Rocky Mountains of North America, and is set nine miles west of the Continental Divide. Topographic relief is significant as the east aspect rises above the Animas River in approximately 1.5 mile. Neighbors include Mount Garfield three miles to the east-southeast, and Twilight Peak, which is the nearest higher peak, 3.7 miles to the south-southwest. This mountain can be seen from U.S. Route 550. The mountain is named after Snowdon, the highest mountain in Wales. Climate According to the Köppen climate classification system, Snowdon Peak is located in an alpine subarctic climate zone with long, cold, snowy winters, and cool to warm summers. Due to its altitude, it receives prec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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