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Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in the dry season. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The mean thickness of a varve here is 0.18 mm, with a minimum thickness of 0.014 mm and maximum of 9.8 mm.Bradley, W. H. The varves and climate of the Green River epoch: U.S. Geol. Survey Prof. Paper 158, pp 87–110, 1929. The sedimentary layers were formed in a large area named for the Green River, a tributary of the Colorado River. The three separate basins lie around the Uinta Mountains (north, east, and south) of northeastern Utah: * an area in northwestern Colorado east ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Butte
Fossil Butte National Monument is a United States National Monument managed by the National Park Service, located west of Kemmerer, Wyoming, United States. It centers on an assemblage of Eocene Epoch (56 to 34 million years ago) animal and plant fossils associated with Fossil Lake—the smallest lake of the three great lakes which were then present in what are now Wyoming, Utah, and Colorado. The other two lakes were Lake Gosiute and Lake Uinta (Ancient lake), Lake Uinta. Fossil Butte National Monument was established as a national monument on October 23, 1972. Fossil Butte National Monument preserves the best paleontological record of Cenozoic aquatic communities in North America and possibly the world, within the 50-million-year-old Green River Formation — the ancient lake bed. Fossils preserved include fish, alligators, bats, turtles, a dog-sized horse, insects, and many other species of plants and animals — suggest that the region was a low, subtropical, freshwater basi ... [...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] |
Siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, pp.381-382 Although its permeability and porosity is relatively low, siltstone is sometimes a tight gas reservoir rock, an unconventional reservoir for natural gas that requires hydraulic fracturing for economic gas production. Siltstone was prized in ancient Egypt for manufacturing statuary and cosmetic palettes. The siltstone quarried at Wadi Hammamat was a hard, fine-grained siltstone that resisted flaking and was almost ideal for such uses. Description There is not complete agreement on the definition of siltstone. One definition is that siltstone is mudrock ( clastic sedimentary rock containing at least 50% clay and silt) in which at least 2/3 of the clay and silt fraction is composed of silt-sized particles. Silt is defined a ... [...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] |
Lithology
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone. Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7. Rock type The naming of a lithology is based on the rock type. The three major rock types are igneous, sedimentary, and metamorphic. Igneous rocks are formed directly from magma, which is a mixture of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wasatch Mountains
The Wasatch Range ( ) or Wasatch Mountains is a mountain range in the western United States that runs about from the Utah-Idaho border south to central Utah. It is the western edge of the greater Rocky Mountains, and the eastern edge of the Great Basin region.''Hiking the Wasatch'', John Veranth, 1988, Salt Lake City, The northern extension of the Wasatch Range, the Bear River Mountains, extends just into Idaho, constituting all of the Wasatch Range in that state. In the language of the native Ute people, Wasatch means "mountain pass" or "low pass over high range." According to William Bright, the mountains were named for a Shoshoni leader who was named with the Shoshoni term ''wasattsi'', meaning "blue heron". In 1926, Cecil Alter quoted Henry Gannett from 1902, who said that the word meant "land of many waters," then posited, "the word is a common one among the Shoshones, and is given to a berry basket" carried by women. Overview Since the earliest days of European sett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Juan Mountains
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] |
Uncompahgre Plateau
The Uncompahgre Plateau in western Colorado is a distinctive large uplift part of the Colorado Plateau. is a Ute word that describes the water: "Dirty Water" or "Rocks that make Water Red". The plateau, with an average elevation of , rises from the Colorado River to Horsefly Peak . It continues on about southeast to the northwest margin of the San Juan Mountains. Its boundaries are the San Miguel and Dolores Rivers to the west, the Colorado River to the north and the Gunnison and Uncompahgre Rivers on the eastern side. Large canyons such as Big Red, Tabeguache, Spring Creek, Roubideau, Escalante, Big Dominquez, and Unaweep are separated by generally flat mesas. The Plateau watersheds include four tributaries of the Colorado River: Dolores River, Gunnison River, San Miguel River and Uncompahgre River. The Uncompahgre Plateau includes about in five counties: Delta, Mesa, Montrose, Ouray, and San Miguel. The plateau is under the management of: * United States Fores ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawatch Range
The Sawatch Range or Saguache RangeThe place name "Saguache” is pronounced “Sawatch” . This name derives from the Ute language noun "''sawup''" meaning "sand dunes" and is spelled using the Spanish language version of this name "Saguache". is a high and extensive mountain range in central Colorado which includes eight of the twenty highest peaks in the Rocky Mountains, including Mount Elbert, at elevation, the highest peak in the Rockies. The range is oriented along a northwest–southeast axis, extending roughly from in the north to in the south. The range contains fifteen peaks in excess of , also known as fourteeners. The range forms a part of the Continental Divide, and its eastern side drains into the headwaters of the Arkansas River. The western side of the range feeds the headwaters of the Roaring Fork River, the Eagle River, and the Gunnison River, tributaries of the Colorado River. The Sawatch mountains in general are high, massive, and relatively gentle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Park Range (Colorado)
The Park Range, elevation approximately , is a mountain range in the Rocky Mountains of northwestern Colorado in the United States. The range forms a relatively isolated part of the Continental Divide, extending north-to-south for approximately along the boundary between Jackson (east) and Routt counties. It separates North Park in the upper basin of the North Platte River on the east from the Elk River basin in the watershed of the Yampa River the west. It rises steeply out of the Yampa River basin, forming a climatic barrier that receives much snowfall in winter. The northern end of the range lies in Wyoming and is known as the Sierra Madre Range. Steamboat Springs, a popular ski resort community, sits on the southwestern flank of the range, at the base of Mount Werner. Much of the range is located within the Routt National Forest, with the summit of the ridge located within the Mount Zirkel Wilderness, named for Mount Zirkel, elevation . The range is prominently visible f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Front Range
The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountered as one goes westbound along the 40th parallel north across the Great Plains of North America. The Front Range runs north-south between Casper, Wyoming, and Pueblo, Colorado, and rises nearly 10,000 feet above the Great Plains. Longs Peak, Mount Evans, and Pikes Peak are its most prominent peaks, visible from the Interstate 25 corridor. The area is a popular destination for mountain biking, hiking, climbing, and camping during the warmer months and for skiing and snowboarding during winter. Millions of years ago, the present-day Front Range was home to ancient mountain ranges, deserts, beaches, and even oceans. The name "Front Range" is also applied to the Front Range Urban Corridor, the populated region of Colorado and Wyoming just ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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