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Whetstone Mountain
Whetstone Mountain, elevation , is a summit in the Gunnison National Forest of western Colorado. The mountain is located south of Crested Butte in Gunnison County. Whetstone Mountain is one of several prominent laccoliths found in the West Elk Mountains. Geology Whetstone Mountain is a laccolith, formed when magma intruded into sedimentary strata of Mancos Shale and the Mesaverde Formation approximately 30 million years ago. Subsequent erosion has removed the softer, overlying sedimentary rock thereby exposing the more resistant igneous rock that characterizes the mountain today. The mountain is composed of quartz monzonite porphyry and granodiorite porphyry. Whetstone Mountain was glaciated, and the most prominent glacial cirques are located on the north side of the mountain. The mountain's name stems from rock collected in the area by the Hayden Survey during the early 1870s. Whetstones (also called hornfels) are contact metamorphic rocks useful for sharpening tools. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Level Datum Of 1929
The National Geodetic Vertical Datum of 1929 is the official name since 1973 of the vertical datum established for vertical control surveying in the United States of America by the General Adjustment of 1929. Originally known as Sea Level Datum of 1929, NGVD 29 was determined and published by the National Geodetic Survey and used to measure the elevation of a point above and depression below mean sea level (MSL). NGVD29 was superseded by the North American Vertical Datum of 1988 (NAVD 88), based upon reference to a single benchmark (referenced to the new International Great Lakes Datum of 1985 local mean sea level height value), although many cities and U.S. Army Corps of Engineers "legacy" projects with established data continued to use the older datum. Methodology Mean sea level was measured at 26 tide gauges: 21 in the United States and 5 in Canada. The datum was defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all benc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Geological significance Igneous and metamorphic rocks make up 90–95% of the top ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of The Most Prominent Summits Of Colorado
The following sortable table comprises the 100 most topographically prominent mountain peaks of the U.S. State of Colorado. Topographic elevation is the vertical distance above the reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface. The topographic prominence of a summit is the elevation difference between that summit and the highest or key col to a higher summit. The topographic isolation of a summit is the minimum great-circle distance to a point of equal elevation. This article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. An ultra-prominent summit is a summit with at least of topographic prominence. There are 126 ultra-prominent summits in the United States. All elevations include an adjustment from the National Geodetic Vertical Datum of 1929 ( NGVD 29) to the North American Vertical Datum of 1988 ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Mountain Peaks Of Colorado
This is a list of major mountain peaks in the U.S. State of Colorado. This article comprises three sortable tables of major mountain peaksThis article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All summits in this article have at least 500 meters of topographic prominence. An ultra-prominent summit is a summit with at least of topographic prominence. in Colorado. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit measures the height of the summit above a geodetic sea level.All elevations in this article include an elevation adjustment from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). For further information, please see this United States National Geodetic Surveybr>noteIf the elevation or prominence of a summit is calculated as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Colorado Fourteeners
This is a list of mountain peaks in the U.S. State of Colorado that exceed of elevation. In the mountaineering parlance of the Western United States, a ''fourteener'' is a mountain peak with an elevation of at least 14,000 feet. This is a complete list of the 53 fourteeners in the U.S. State of Colorado with at least of topographic prominence. See the main fourteener article, which has a list of all of the fourteeners in the United States, for some information about how such lists are determined and caveats about elevation and ranking accuracy. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit measures the height of the summit above a geodetic sea level.All elevations in the 48 states of the contiguous United States include an elevation adjustment from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). For further information, please see this Uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Mountains Of The United States
This list includes significant summit (topography), mountain peaks and summit (topography), high points located in the United States arranged alphabetically by U.S. state, state, District of Columbia, district, or Territories of the United States, territory. The highest peak or point in each state, district or territory is noted in bold. Significant mountain peaks and high points Alabama *Brindley Mountain *Cheaha Mountain, highest summit in the Alabama, State of Alabama *Monte Sano Mountain *Capshaw Mountain *Dirtseller Mountain *Frog Mountain *Hawk Pride Mountain *Gunters Mountain *Sand Mountain (Alabama) *Keel Mountain (Alabama) *Halama Mountain Alaska * Afognak Mountain, summit of Afognak Island * Amak Volcano, active stratovolcano * Amherst Peak * Amulet Peak * Andy Simons Mountain * Annex Peak * Anvil Peak , active stratovolcano that forms the summit of Semisopochnoi Island * Arthur Peak * Asses Ears (Alaska) * Atna Peaks * Atuk Mountain , summit of St. L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Mountain Ranges Of Colorado
This is a list of the major mountain ranges in the U.S. State of Colorado. All of these ranges are considered subranges of the Southern Rocky Mountains. As given in the table, topographic elevation is the vertical distance above the reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface. The topographic prominence of a summit is the elevation difference between that summit and the highest or key col to a higher summit. The topographic isolation of a summit is the minimum great-circle distance to a point of equal elevation. All elevations in this article include an elevation adjustment from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). For further information, please see this United States National Geodetic Surveybr>note If an elevation or prominence is calculated as a range of values, the arithmetic mean is shown. __TOC__ Mountain ranges Gallery Image:Moun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Metamorphic
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrologists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hornfels
Hornfels is the group name for a set of contact metamorphic rocks that have been baked and hardened by the heat of intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases exceedingly tough and durable. These properties are due to fine grained non-aligned crystals with platy or prismatic habits, characteristic of metamorphism at high temperature but without accompanying deformation. The term is derived from the German word ''Hornfels'', meaning "hornstone", because of its exceptional toughness and texture both reminiscent of animal horns. These rocks were referred to by miners in northern England as whetstones. Most hornfels are fine-grained, and while the original rocks (such as sandstone, shale, slate and limestone) may have been more or less fissile owing to the presence of bedding or cleavage planes, this structure is effaced or rendered inoperative in the hornfels. Though many hornfels show vestiges of the original bedding, they break ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological And Geographical Survey Of The Territories
The United States Geological and Geographical Survey of the Territories was established by an act of Congress on 2 March 1867 as an agency under the Department of the Interior (later the General Land Office) tasked to complete a geographical survey of the State of Nebraska which had been admitted to the Union the day before. The scope of the survey eventual grew to include all the American territories adjacent to the Rocky Mountains encompassing hundreds of thousands of square miles. The survey over its existence was headed by Dr. Ferdinand Vandeveer Hayden who published a number of reports between 1867 and 1883 on the region’s geography, geology, topography, ethnology, philology, paleontology Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ... and other allied subjects. Congress ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cirque
A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform arising from fluvial erosion. The concave shape of a glacial cirque is open on the downhill side, while the cupped section is generally steep. Cliff-like slopes, down which ice and glaciated debris combine and converge, form the three or more higher sides. The floor of the cirque ends up bowl-shaped, as it is the complex convergence zone of combining ice flows from multiple directions and their accompanying rock burdens. Hence, it experiences somewhat greater erosion forces and is most often overdeepened below the level of the cirque's low-side outlet (stage) and its down-slope (backstage) valley. If the cirque is subject to seasonal melting, the floor of the cirque most often forms a tarn (small lake) behind a dam, which marks the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water. On Earth, 99% of glacial ice is contained within vast ice sheets (also known as "continental glaciers") in the polar regions, but glaciers may be found in mountain ranges on every continent other than the Australian mainland, including Oceania's high-latitude oceanic island countries such as New Zealand. Between latitudes 35°N and 35°S, glaciers occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
