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64-596: Horseshoe Canyon , formerly known as Barrier Canyon , is in a remote area west of the Green River and north of the Canyonlands National Park Maze District in Utah , United States. It is known for its collection of Barrier Canyon Style (BCS) rock art, including both pictographs and petroglyphs , which was first recognized as a unique style here. A portion of Horseshoe Canyon containing The Great Gallery

128-576: A larger deposit of oil shale in the Green River formation. The Equity Oil Company currently has 17 wells in declining production of oil near Ashley Field and is looking to inject carbon dioxide into the Weber reservoir to increase the rate of oil flow through their pipelines. At the time of its discovery (2005), the Green River Formation was said to have the world's largest fossil fuel deposits in

192-786: A major generator of silt, which accumulated to form the fertile soils of north India and Bangladesh, and the loess of central Asia and north China. Loess has long been thought to be absent or rare in deserts lacking nearby mountains (Sahara, Australia). However, laboratory experiments show eolian and fluvial processes can be quite efficient at producing silt, as can weathering in tropical climates. Silt seems to be produced in great quantities in dust storms, and silt deposits found in Israel, Tunisia, Nigeria, and Saudi Arabia cannot be attributed to glaciation. Furthermore, desert source areas in Asia may be more important for loess formation than previously thought. Part of

256-561: A nomadic group of hunter-gatherers predating the Fremont and Ancestral Puebloans. The panel itself measures about 200 feet (61 m) long and 15 feet (4.6 m) high. The panel contains about 20 life-sized anthropomorphic images, the largest of which measures over 7 feet (2.1 m) tall. A Works Projects Administration produced reproduction of the paintings is located at the Natural History Museum of Utah . The Holy Ghost panel of

320-440: A number of mechanisms. However, the main process is likely abrasion through transport, including fluvial comminution , aeolian attrition and glacial grinding. Because silt deposits (such as loess , a soil composed mostly of silt ) seem to be associated with glaciated or mountainous regions in Asia and North America, much emphasis has been placed on glacial grinding as a source of silt. High Asia has been identified as

384-592: A panic caused by the Meeker Massacre in Colorado. Most of the land in the valley of the river today is owned and controlled by the federal government. Private holdings are largely limited to bottoms. Until the 1940s, the valley's economy was based largely on ranching. Tourism has emerged as the dominant industry in the region in the last several decades. A proposed nuclear power plant, the Blue Castle Project ,

448-482: A platy or bladed shape. This may be characteristic of how larger grains abrade, or reflect the shape of small quartz grains in foliated metamorphic rock , or arise from authigenic growth of quartz grains parallel to bedding in sedimentary rock . Theoretically, particles formed by random fracturing of an isotropic material, such as quartz, naturally tend to be blade-shaped. The size of silt grains produced by abrasion or shattering of larger grains may reflect defects in

512-674: A pollutant in water the phenomenon is known as siltation . Silt deposited by the Mississippi River throughout the 20th century has decreased due to a system of levees , contributing to the disappearance of protective wetlands and barrier islands in the delta region surrounding New Orleans . In southeast Bangladesh, in the Noakhali district , cross dams were built in the 1960s whereby silt gradually started forming new land called "chars". The district of Noakhali has gained more than 73 square kilometres (28 sq mi) of land in

576-602: A tributary of the Colorado River came about mainly for political reasons. In earlier nomenclature, the Colorado River began at its confluence with the Green River. Above the confluence, Colorado was called the Grand River. In 1921, U.S. Representative Edward T. Taylor of Colorado petitioned the Congressional Committee on Interstate and Foreign Commerce to rename the Grand River as the Colorado River. On July 25, 1921,

640-456: A wintering ground for American trappers in the next decades, with trading posts established at the mouth of the White near Whiterocks, Utah , and Browns Park . The Upper Green River Rendezvous Site near Pinedale, Wyoming was a popular location for annual mountain man rendezvous during the 1820s and 1830s, with as many as 450 to 500 trappers attending during its heyday in the 1830s. The region

704-615: Is a particular challenge for civil engineering . The failure of the Teton Dam has been attributed to the use of loess from the Snake River floodplain in the core of the dam. Loess lacks the necessary plasticity for use in a dam core, but its properties were poorly understood, even by the U.S. Bureau of Reclamation , with its wealth of experience building earthen dams . Silt is susceptible to liquefaction during strong earthquakes due to its lack of plasticity. This has raised concerns about

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768-703: Is carried through the vadose zone to be deposited in pore space. ASTM American Standard of Testing Materials: 200 sieve – 0.005 mm. USDA United States Department of Agriculture 0.05–0.002 mm. ISSS International Society of Soil Science 0.02–0.002 mm. Civil engineers in the United States define silt as material made of particles that pass a number 200 sieve (0.074 mm or less) but show little plasticity when wet and little cohesion when air-dried. The International Society of Soil Science (ISSS) defines silt as soil containing 80% or more of particles between 0.002 mm to 0.02 mm in size while

832-589: Is common throughout the geologic record , but it seems to be particularly common in Quaternary formations. This may be because deposition of silt is favored by the glaciation and arctic conditions characteristic of the Quaternary. Silt is sometimes known as rock flour or glacier meal , especially when produced by glacial action. Silt suspended in water draining from glaciers is sometimes known as rock milk or moonmilk . A simple explanation for silt formation

896-458: Is good agreement between these definitions in practice. The upper size limit of 1/16 mm or 63 microns corresponds to the smallest particles that can be discerned with the unaided eye. It also corresponds to a Tanner gap in the distribution of particle sizes in sediments : Particles between 120 and 30 microns in size are scarce in most sediments, suggesting that the distinction between sand and silt has physical significance. As noted above,

960-625: Is joined by the Duchesne River , and three miles (5 km) farther downstream by the White River . Ten miles farther downstream, it is joined by the Willow River . South of the plateau, it is joined by Nine Mile Creek , then enters the Roan Cliffs where it flows south through the back-to-back Desolation and Gray canyons, with a combined length of 120 mi (192 km). In Gray Canyon, it

1024-567: Is joined by the Price River . South of the canyon, it passes the town of Green River, Utah and is joined by the San Rafael River in southern Emery County . In eastern Wayne County it meanders through Canyonlands National Park , where it joins Colorado. The Flaming Gorge Dam in Utah is a significant regional source of water for irrigation and mining, as well as for hydroelectric power. Begun in

1088-411: Is less expensive for the production of soda ash in the United States than the synthetic Solvay process , which predominates in the rest of the world. The area has been mined for uranium . Silt Silt is a common material, making up 45% of average modern mud . It is found in many river deltas and as wind-deposited accumulations, particularly in central Asia, north China, and North America. It

1152-544: Is navigable by small craft throughout its course and by large motorboats upstream to Flaming Gorge Dam. Near the areas where the Oregon Trail crosses the river, it is 400 to 500 feet (120 to 150 m) wide and averages about 20 feet (6.1 m) deep at normal flow. Archaeological evidence indicates that the tributary canyons and sheltered areas in the river valley were home to the Fremont Culture , which flourished from

1216-729: Is now known as Sevier Lake . Later cartographers extended the error, representing the Buenaventura River as flowing into the Pacific Ocean . At least one charted the Buenaventura as draining the Great Salt Lake . Later, Spanish and Mexican explorers adopted the name Rio Verde, meaning "Green River" in Spanish . Exactly when the Spanish started using this name and why is unknown. Explanations of

1280-413: Is often found in mudrock as thin laminae , as clumps, or dispersed throughout the rock. Laminae suggest deposition in a weak current that winnows the silt of clay, while clumps suggest an origin as fecal pellets . Where silt is dispersed throughout the mudrock, it likely was deposited by rapid processes, such as flocculation . Sedimentary rock composed mainly of silt is known as siltstone . Silt

1344-466: Is part of a detached unit of Canyonlands National Park . The Horseshoe Canyon Unit was added to the park in 1971 in an attempt to preserve and protect the rock art found along much of its length. Human presence in Horseshoe Canyon has been dated as far back as 9000-7000 B.C., when Paleo-Indians hunted large mammals such as mastodons and mammoths across the southwest. Later inhabitants included

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1408-441: Is produced in both very hot climates (through such processes as collisions of quartz grains in dust storms ) and very cold climates (through such processes as glacial grinding of quartz grains.) Loess is soil rich in silt which makes up some of the most fertile agricultural land on Earth. However, silt is very vulnerable to erosion, and it has poor mechanical properties, making construction on silty soil problematic. The failure of

1472-497: Is set to begin construction near Green River in 2023. The plant will use 53,500 acre-feet (66,000,000 m ) of water annually from the Green River once both reactors are commissioned. The La Barge oil field was discovered in 1924. Oil was produced from Tertiary sandstones ( Wasatch Formation and Green River Formation ), within an anticline 600 to 1200 feet deep. The Big Piney -La Barge complex has produced gas since 1956 and oil since 1960. Cumulative production by 1976

1536-634: Is that it is a straightforward continuation to a smaller scale of the disintegration of rock into gravel and sand. However, the presence of a Tanner gap between sand and silt (a scarcity of particles with sizes between 30 and 120 microns) suggests that different physical processes produce sand and silt. The mechanisms of silt formation have been studied extensively in the laboratory and compared with field observations. These show that silt formation requires high-energy processes acting over long periods of time, but such processes are present in diverse geologic settings. Quartz silt grains are usually found to have

1600-622: Is that it is detrital particles with sizes between 1/256 and 1/16 mm (about 4 to 63 microns). This corresponds to particles between 8 and 4 phi units on the Krumbein phi scale . Other geologists define silt as detrital particles between 2 and 63 microns or 9 to 4 phi units. A third definition is that silt is fine-grained detrital material composed of quartz rather than clay minerals . Since most clay mineral particles are smaller than 2 microns, while most detrital particles between 2 and 63 microns in size are composed of broken quartz grains, there

1664-662: Is the subject of the song "Green River" by C.W. McCall . The headwaters of the Green River is in western Wyoming, in northern Sublette County , on the western side of the Continental Divide in the Wind River Range and the Bridger–Teton National Forest . It flows south through Sublette County and western Wyoming in an area known as the Upper Green River Valley, then southwest and is joined by

1728-597: The Big Sandy River in western Sweetwater County . At the town of La Barge, it flows into Fontenelle Reservoir , formed by Fontenelle Dam. Below the dam, it flows through open sage-covered rolling prairie where it is crossed by the Oregon , California and Mormon emigration trails, and then further south past the town of Green River, Wyoming and into the Flaming Gorge Reservoir in southwestern Wyoming, formed by

1792-888: The Canyon of the Lodore (otherwise known as the Gates of Lodore) and is joined by the Yampa River at Steamboat Rock . It turns westward back into Utah along the southern edge of the Uintas in Whirlpool Canyon . In Utah, it meanders southwest across the Yampa Plateau and through the Uintah and Ouray Indian Reservation and the Ouray National Wildlife Refuge . Two miles south of Ouray, Utah , it

1856-701: The Flaming Gorge Dam in northeastern Utah. Before the reservoir's creation, the Blacks Fork joined the Green River south of the town of Green River, but today the mouth of Blacks Fork is submerged by the reservoir. South of the dam, it is forced to turn sharply eastward by the uplift of the Uinta Mountains , looping around the eastern tip of the range as it travels from Utah into northwestern Colorado and through Browns Park before turning west and then south into Dinosaur National Monument , where it passes through

1920-583: The Nile and Niger River deltas. Bangladesh is largely underlain by silt deposits of the Ganges delta. Silt is also abundant in northern China, central Asia, and North America. However, silt is relatively uncommon in the tropical regions of the world. Silt is commonly found in suspension in river water, and it makes up over 0.2% of river sand. It is abundant in the matrix between the larger sand grains of graywackes . Modern mud has an average silt content of 45%. Silt

1984-472: The Oregon , California , and Mormon emigration trails. Nearly all primary emigration routes had to cross the Green River. The main trail crossed near where the Big Sandy River joins the Green River in Wyoming. The river is too big and much too deep to ford at any time of the year and is the largest, most dangerous river crossed by the Oregon Trail. For that reason, ferries were commonly run on this stretch of

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2048-461: The Teton Dam in 1976 has been attributed to the use of unsuitable loess in the dam core, and liquefication of silty soil is a significant earthquake hazard. Windblown and waterborne silt are significant forms of environmental pollution, often exacerbated by poor farming practices. Silt is detritus (fragments of weathered and eroded rock) with properties intermediate between sand and clay . A more precise definition of silt used by geologists

2112-602: The 1950s and finished in 1963, it was highly controversial and opposed by conservationists. Originally, a dam was to be built in Whirlpool Canyon, but the conservationist movement traded the Flaming Gorge Dam for halting that proposal. The Green is a large, deep, powerful river. It ranges from 100 to 300 feet (30 to 100 m) wide in the upper course and from 300 to 1,500 feet (91 to 457 m) wide in its lower course, and from 3 to 50 feet (0.91 to 15.24 m) in depth. It

2176-515: The 7th century to the 13th century. The Fremont were semi-nomadic people who lived in pithouses and are best known for the rock art on canyon walls and in sheltered overhangs. In later centuries, the river basin was home to the Shoshone and Ute peoples, both nomadic hunters. The Shoshone inhabited the river valley north of the Uinta Mountains , whereas the Utes lived to the south. The current reservation of

2240-566: The Desert Archaic culture, the Fremont culture , and Ancestral Puebloans . Occupation by the Fremont and Ancestral Puebloans was relatively brief; it is believed that the canyon was abandoned by Native American peoples by 1300 A.D. The Great Gallery is one of the largest and best preserved collections of Barrier Canyon Style rock art. The gallery was a product of the Desert Archaic culture,

2304-582: The Great Gallery has been dated to between 400 A.D. and 1100 A.D. by dating two rockfall events of which one exposed the rock face the panel on which it was made and the second damaging part of the panel. The Horseshoe Canyon trailhead is located on the west rim of the canyon. It can be accessed from State Route 24 via 30 miles (48 km) of graded dirt road, or from Green River via 47 miles (76 km) of dirt road. Both routes include segments of road that may become impassable when wet. Visitors may camp at

2368-531: The Great Gallery is roughly 6.5 miles (10.5 km) round trip, and requires 3 to 6 hours to complete. The trail is fairly well marked, but reaching the Great Gallery requires a certain amount of stamina and endurance, particularly in the heat. Three other significant panels of rock art are passed en route to the Great Gallery. 38°27′15″N 110°12′32″W  /  38.45417°N 110.20889°W  / 38.45417; -110.20889 Green River (Colorado River tributary) The Green River , located in

2432-558: The Native Americans). A map of 1847 redirects the course of the Rafael to the north and labels it as Green River. It would be some time before the true confluence of the Green and Colorado Rivers would be known. The Old Spanish Trail from New Mexico to California crossed the river just above the present-day town of Green River, Utah. In the early 19th century, the upper river in Wyoming

2496-430: The U.S. Department of Agriculture puts the cutoff at 0.05mm. The term silt is also used informally for material containing much sand and clay as well as silt-sized particles, or for mud suspended in water. Silt is a very common material, and it has been estimated that there are a billion trillion trillion (10 ) silt grains worldwide. Silt is abundant in eolian and alluvial deposits, including river deltas , such as

2560-646: The Utes is in the Uintah Basin . The Shoshone called the river the Seeds-kee-dee-Agie , meaning "Prairie Hen River." In 1776, the Spanish friars Silvestre Vélez de Escalante and Francisco Atanasio Domínguez crossed the river near present-day Jensen, naming it the Rio de San Buenaventura . The map-maker of the expedition, Captain Bernardo Miera y Pacheco , erroneously indicated that the river flowed southwest to what

2624-462: The canyons, geographic features, and rapids along the river. For example, "we sweep around another great bend to the left, making a circuit of nine miles, and come back to a point within 600 feet of the beginning of the bend. In the two circuits, we describe almost in figure 8. The men call it a `bowknot' of a river; so we name it Bowknot Bend ." (Powell, 1869) From the 1840s through the 1860s, hundreds of thousands of emigrants made their way west along

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2688-513: The crystal structure of the quartz, known as Moss defects. Such defects are produced by tectonic deformation of the parent rock, and also arise from the high-low transition of quartz: Quartz experiences a sharp decrease in volume when it cools below a temperature of about 573 °C (1,063 °F), which creates strain and crystal defects in the quartz grains in a cooling body of granite. Mechanisms for silt production include: Laboratory experiments have produced contradictory results regarding

2752-548: The earthquake damage potential in the silty soil of the central United States in the event of a major earthquake in the New Madrid Seismic Zone . Silt is easily transported in water and is fine enough to be carried long distances by air in the form of dust . While the coarsest silt particles (60 micron) settle out of a meter of still water in just five minutes, the finest silt grains (2 microns) can take several days to settle out of still water. When silt appears as

2816-466: The effectiveness of various silt production mechanisms. This may be due to the use of vein or pegmatite quartz in some of the experiments. Both materials form under conditions promoting ideal crystal growth, and may lack the Moss defects of quartz grains in granites. Thus production of silt from vein quartz is very difficult by any mechanism, whereas production of silt from granite quartz proceeds readily by any of

2880-443: The fine silt produced in dust storms and the coarse silt fraction possibly representing the fine particle tail of sand production. Loess underlies some of the most productive agricultural land worldwide. However, it is very susceptible to erosion. The quartz particles in silt do not themselves provide nutrients, but they promote excellent soil structure , and silt-sized particles of other minerals, present in smaller amounts, provide

2944-543: The form of a solid rock resource called oil shale . There is estimated to be between 500 billion and 1.1 trillion barrels (80 and 175 km ) of potentially recoverable oil in the basin, however; this estimated amount of recoverable oil in the form of kerogen is challenged, and in doubt, as currently there is no economically feasible technology to convert rock into a permeable oil. Kerogen is an uncooked form of hydrocarbon that nature did not convert into actual oil. The cost of converting Green River oil shale into actual oil at

3008-401: The laboratory using the pipette method, which is based on settling rate via Stokes' law and gives the particle size distribution accordingly. The mineral composition of silt particles can be determined with a petrographic microscope for grain sizes as low as 10 microns. Vadose silt is silt-sized calcite crystals found in pore spaces and vugs in limestone . This is emplaced as sediment

3072-416: The lower limit of 2 to 4 microns corresponds to the transition from particles that are predominantly broken quartz grains to particles that are predominantly clay mineral particles. Assallay and coinvestigators further divide silt into three size ranges: C (2–5 microns), which represents post-glacial clays and desert dust; D1 (20–30 microns) representing "traditional" loess ; and D2 (60 microns) representing

3136-446: The moment would be higher than what it could be sold for. The EROI for oil shale is very low while having a very high destructive environmental impact. The Green River Basin contains the world's largest known deposit of trona ore near Green River, Wyoming. Soda ash mining from trona veins 900 and 1600 feet (300 and 500 m) deep is a major industrial activity in the area, employing over 2000 persons at four mines. The mining operation

3200-477: The name "Green" include ideas about the color of the water (though it is usually just as red as that of the Colorado), the color of soapstone along its banks, the color of the vegetation, and the name of a trapper. No explanation can be verified. Wilson Hunt of John Jacob Astor 's Pacific Fur Company called it The Spanish River in 1811. By that time it was clear to the trappers that Miera's map (if they had seen it)

3264-586: The name change was made official in House Joint Resolution 460 of the 66th Congress , over the objections of representatives from Wyoming and Utah and the United States Geological Survey , which noted that the drainage basin of the Green River was more extensive than that of the Grand River, although the Grand carried a higher volume of water at its confluence with the Green. The Green River

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3328-762: The necessary nutrients. Silt, deposited by annual floods along the Nile River , created the rich, fertile soil that sustained the Ancient Egyptian civilization. The closure of the Aswan High Dam has cut off this source of silt, and the fertility of the Nile delta is deteriorating. Loess tends to lose strength when wetted, and this can lead to failure of building foundations. The silty material has an open structure that collapses when wet. Quick clay (a combination of very fine silt and clay-sized particles from glacial grinding)

3392-507: The past 50 years. With Dutch funding, the Bangladeshi government began to help develop older chars in the late 1970s, and the effort has since become a multi-agency operation building roads, culverts , embankments, cyclone shelters, toilets and ponds, as well as distributing land to settlers. By fall 2010, the program will have allotted some 100 square kilometres (20,000 acres) to 21,000 families. A main source of silt in urban rivers

3456-440: The problem may be the conflation of high rates of production with environments conducive to deposition and preservation, which favors glacial climates more than deserts. Loess associated with glaciation and cold weathering may be distinguishable from loess associated with hot regions by the size distribution. Glacial loess has a typical particle size of about 25 microns. Desert loess contains either larger or smaller particles, with

3520-586: The river. Some popular ferries included the Lombard and Robinson ferries at the main crossing and the Mormon, Mountain Man, and Names Hill ferries where the popular Sublette-Greenwood cutoff crossed the river further upstream. In 1878 the first permanent settlement in the river valley was founded at Vernal by a party of Mormons led by Jeremiah Hatch . The settlement survived a diphtheria epidemic its first winter, as well as

3584-402: The route traverses the arid Colorado Plateau , where the river has carved some of the most spectacular canyons in the United States. The Green is slightly smaller than Colorado when the two rivers merge but typically carries a larger load of silt . The average yearly mean flow of the river at Green River, Utah is 6,121 cubic feet (173.3 m ) per second. The status of the Green River as

3648-579: The trappers and American explorers. While it was known that the Green River drained to Colorado, the exact course was not known. Miera's map showed the Colorado River branching into two major streams – the Nabajoo (San Juan) and the Zaguananas. It also showed the Zaguananas branching into four heads, including the Dolores and the Rafael (the latter of which Escalante's journal equates with Colorado per information from

3712-413: The very coarse North African loess. Silt can be distinguished from clay in the field by its lack of plasticity or cohesiveness and by its grain size. Silt grains are large enough to give silt a gritty feel, particularly if a sample is placed between the teeth. Clay-size particles feel smooth between the teeth. The proportions of coarse and fine silt in a sediment sample are determined more precisely in

3776-559: The west rim trailhead, on public land managed by the Bureau of Land Management , or BLM. A vault toilet is provided but there is no water available. Overnight camping is not permitted in Horseshoe Canyon inside the Park boundaries. To see the rock art, visitors must descend 750 vertical feet (228 m) to the canyon bottom and hike approximately 3 miles (4.8 km). The hike from the West Rim trailhead to

3840-631: The western United States, is the chief tributary of the Colorado River . The watershed of the river, known as the Green River Basin , covers parts of the U.S. states of Wyoming , Utah , and Colorado . The Green River is 730 miles (1,170 km) long, beginning in the Wind River Mountains of Wyoming and flowing through Wyoming and Utah for most of its course, except for a short segment of 40 miles (64 km) in western Colorado. Much of

3904-400: Was 65 million bbl of oil and over 1.2 Tcf (trillion cubic feet ) of gas. Production includes the Cretaceous Mesaverde Formation and Frontier Formation . The discovery of petroleum at the Ashley Field after World War II has led to the exploitation of oil and natural gas in the region. The oil at Ashley Field is trapped in Aeolin deposits of "coversands and loess," while there is

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3968-415: Was explored by John C. Fremont on several of his expeditions in the 1840s. Fremont corrected the cartographic error of Miera, establishing firmly that the river did not drain the Great Salt Lake. In 1869, the river was surveyed and mapped by John Wesley Powell as part of the first of his two expeditions to the region. During his two voyages in 1869 and 1871, he and his men gave most of the current names of

4032-405: Was part of the disputed Oregon Country . It was explored by trappers from the North West Company and Hudson's Bay Company , such as Donald Mackenzie who pioneered the area from 1819. In 1825, the American William Ashley and a party of American explorers floated down the river from north of the Uintah Mountains to the mouth of the White River . The valley of the river became increasingly used as

4096-461: Was wrong, for they had learned from the Native Americans that the Green River drained to the Colorado River and the Gulf of California . When Jedediah Smith reached the lower Colorado in 1826, he first called it the Seedskeedee, as the Green/Colorado River was commonly known among the trappers. By the time of Bonneville's expedition in 1832, the names "Seeds-kee-dee", "Spanish River", "Green River", and even "Colorado River" were used interchangeably by

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