1.
United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
2.
Idaho
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Idaho is a state in the northwestern region of the United States. It borders the state of Montana to the east and northeast, Wyoming to the east, Nevada and Utah to the south, to the north, it shares a small portion of the Canadian border with the province of British Columbia. With a population of around 1.7 million people and an area of 83,569 square miles, Idaho is the 14th largest, the states capital and largest city is Boise. Idaho prior to European settlement was inhabited solely by Native American peoples, in the early 19th century, Idaho was considered part of the Oregon Country, an area disputed between the U. S. and the United Kingdom. Idaho was eventually admitted to the Union on July 3,1890, forming part of the Pacific Northwest, Idaho is divided into several distinct geographic and climatic regions. In the states north, the relatively isolated Idaho Panhandle is closely linked with Eastern Washington, the states south includes the Snake River Plain, while the south-east incorporates part of the Great Basin. Idaho is quite mountainous, and contains several stretches of the Rocky Mountains, additionally, around 38 percent of Idahos land is held by the United States Forest Service, the most of any state. Industries significant for the economy include manufacturing, agriculture, mining, forestry. Idahos agricultural sector supplies a number of different products, but the state is best known for its potato crop, the official state nickname is the Gem State, which references Idahos reputation for gemstones and, more broadly, its many wilderness areas. The exact origin of the remains a mystery. Willing later claimed that he had invented the name. Congress ultimately decided to name the area Colorado Territory when it was created in February 1861, thinking they would get a jump on the name, locals named a community in Colorado Idaho Springs. However, the name Idaho did not fall into obscurity, the same year Congress created Colorado Territory, a county called Idaho County was created in eastern Washington Territory. The county was named after a steamship named Idaho, which was launched on the Columbia River in 1860 and it is unclear whether the steamship was named before or after Willings claim was revealed. Regardless, a portion of Washington Territory, including Idaho County, was used to create Idaho Territory in 1863. Despite this lack of evidence for the origin of the name, the name Idaho may be derived from the Plains Apache word ídaahę́, which means enemy. The Comanches used this word to refer to the Idaho Territory, a 1956 Idaho history textbook says, Idaho is a Shoshoni Indian exclamation. The word consists of three parts, the first is Ee, which in English conveys the idea of coming down
3.
Nevada
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Nevada is a state in the Western, Mountain West, and Southwestern regions of the United States of America. Nevada is the 7th most extensive, the 34th most populous, nearly three-quarters of Nevadas people live in Clark County, which contains the Las Vegas–Paradise metropolitan area where three of the states four largest incorporated cities are located. Nevada is officially known as the Silver State because of the importance of silver to its history and economy. It is also known as the Battle Born State, because it achieved statehood during the Civil War, as the Sage-brush State, for the plant of the same name. Nevada borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, Nevada is largely desert and semi-arid, much of it located within the Great Basin. Areas south of the Great Basin are located within the Mojave Desert, while Lake Tahoe, about 86% of the states land is managed by various jurisdictions of the U. S. federal government, both civilian and military. Before European contact, Native Americans of the Paiute, Shoshone, the first Europeans to explore the region were Spanish. They called the region Nevada because of the snow covered the mountains in winter. The area formed part of the Viceroyalty of New Spain, the United States annexed the area in 1848 after its victory in the Mexican–American War, and it was incorporated as part of Utah Territory in 1850. The discovery of silver at the Comstock Lode in 1859 led to a boom that became an impetus to the creation of Nevada Territory out of western Utah Territory in 1861. Nevada became the 36th state on October 31,1864, as the second of two added to the Union during the Civil War. Nevada has a reputation for its libertarian laws, in 1940, with a population of just over 110,000 people, Nevada was by far the least-populated state, with less than half the population of the next least-populated state. However, legalized gambling and lenient marriage and divorce laws transformed Nevada into a major tourist destination in the 20th century, Nevada is the only U. S. state where prostitution is legal, though it is illegal in Clark County, Washoe County and Carson City. The tourism industry remains Nevadas largest employer, with mining continuing as a sector of the economy. The name Nevada comes from the Spanish nevada, meaning snow-covered, most Nevadans pronounce the second syllable of their state name using the vowel of trap. Many from outside the Western United States pronounce it with the vowel of father, although the latter pronunciation is closer to the Spanish pronunciation, it is not the pronunciation preferred by most Nevadans. State Assemblyman Harry Mortenson proposed a bill to recognize the alternate pronunciation of Nevada, though the bill was not supported by most legislators, the Nevadan pronunciation is the de facto official one, since it is the one used by the state legislature. Nevada is almost entirely within the Basin and Range Province, and is broken up by many mountain ranges
4.
Owyhee County, Idaho
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Owyhee County is a county located in the southwestern corner of the U. S. state of Idaho. As of the 2010 census, the population was 11,526, the county seat is Murphy, and its largest city is Homedale. In area it is the second-largest county in Idaho, behind Idaho County, Owyhee County is part of the Boise, ID Metropolitan Statistical Area. It is the location of more than 50% of the Duck Valley Indian Reservation. The majority of the federally recognized Shoshone-Paiute Tribe that is associated with this reservation lives on the Nevada side, its center is in Owyhee. This area was the territory of Western Shoshone, Northern Paiute and Bannock peoples, conflicts over land use and resources led to the indigenous peoples being pushed aside. On December 31,1863, Owyhee County became the first county organized by the Idaho Territory Legislature, while Boise, Idaho, Nez Perce and Shoshone counties were organized under the laws of Washington Territory, they were not recognized by the Idaho Territory until February 1864. The original county seat at Ruby City was moved to nearby Silver City in 1867, Owyhee Countys original boundary was the portion of Idaho Territory south of the Snake River and west of the Rocky Mountains. Less than a month after the creation of Owyhee County, Oneida County was formed in January 1864 from the portion of the county. The formation of Cassia County in 1879 took further territory in the east, Owyhee Countys history is closely linked to the mining boom that dominated Idaho Territory in the second half of the 19th century. Silver City and Ruby City developed as boom towns, at its height in the 1880s, Owyhee County was among the most populous places in Idaho. Today it is among the least populous, at 1.4 persons per square mile, in 1886 the reservation was expanded to accommodate people of the Northern Paiute. In the 20th century the combined and are federally recognized as a single government. The majority of the live on the Nevada side of the reservation. Owyhee County gained its present boundaries in 1930 after an election approved moving a portion of it near Glenns Ferry, in 1934 the county seat was moved from the nearly abandoned Silver City to its present location in Murphy. In the 21st century, both Silver City and Ruby City are ghost towns, remnant of the mining boom, the name Owyhee derives from an early anglicization of the Hawaiian term Hawaiʻi. When James Cook encountered what he named the Sandwich Islands in 1778, he found them inhabited by Native Hawaiians, noted for their hardy physique and maritime skills, numerous Native Hawaiians were hired as crew members aboard European and American vessels. Many Owyhee sailed to the American Northwest coast and found employment along the Columbia River, in 1819, three Owyhee joined Donald Mackenzies Snake expedition, which went out annually into the Snake country for the North West Company, a Montreal-based organization of Canadian fur traders
5.
Elko County, Nevada
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Elko County is a county located in the northeastern corner of the U. S. state of Nevada. As of the 2010 census, the population was 48,818, the county was established on March 5,1869, from Lander County. Elko County is the fourth-largest county by area in the contiguous United States and it is one of only 10 counties in the U. S. with more than 10,000 square miles of area. Elko County is part of the Elko, NV Micropolitan Statistical Area and it contains 49.8 percent of the Duck Valley Indian Reservation, set up in the late 19th century for the Shoshone-Paiute peoples, they are a federally recognized tribe. Although slightly more than 50% of the reservation is located across the border in Owyhee County, Idaho, the total land area of the reservation is 450.391 square miles. This area was occupied by Native American tribes of the Plateau, particularly the Western Shoshone, Northern Paiute. Their traditional ways were disrupted after European-American settlement, as the two competed for resources and had differing conceptions of land use and property. Elko County was established by European Americans in 1869 from Lander County, the federally recognized tribe of the two peoples together conducts farming and ranching in this high desert territory. The population of the county increased markedly in the late 20th century as the economy improved, on March 14,2014, the Bureau of Land Management sold 29 oil and gas leases for $1.27 million to a collection of six companies that included Noble Energy. The transaction was the first such in Nevada, according to the U. S. Census Bureau, the county has a total area of 17,203 square miles, of which 17,170 square miles is land and 33 square miles is water. Not counting Alaskas boroughs, it is the fourth-largest county in area in the United States. The elevation ranges from about 4,300 feet at the edge of the flats of the Great Salt Lake Desert. The most topographically prominent mountain in Elko County is Pilot Peak, the county has three physiographic sections and 4 watersheds. As of the census of 2000, there were 45,291 people,15,638 households, the population density was 3/sq mi. There were 18,456 housing units at a density of 1/sq mi. The racial makeup of the county was 82. 04% White,0. 59% Black or African American,5. 30% Native American,0. 68% Asian,0. 11% Pacific Islander,8. 50% from other races, and 2. 78% from two or more races. 19. 73% of the population were Hispanic or Latino of any race,20. 90% of all households were made up of individuals and 4. 80% had someone living alone who was 65 years of age or older. The average household size was 2.85 and the family size was 3.33
6.
Jarbidge River
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The Jarbidge River is a 51. 8-mile-long, high altitude river in northern Nevada and southwest Idaho in the United States. The small town of Jarbidge, Nevada is located on the main stream, for approximately 28 miles this narrow river twists and turns northwest through a remarkable canyon, deep and rugged, but often dotted with groves of juniper trees along the banks. The Jarbidge Canyon is about 650 feet deep at the confluence of the forks, tributaries include Buck Creek, Dave Creek, Columbet Creek, Dorsey Creek, Cougar Creek, and Poison Creek. The river is cold, though swimming is possible, there is a danger of hypothermia. Kayaking is possible in certain sections in early summer, class IV, the river can also be run by experienced rafters. For rafters, the run can be arduous, with log jams inevitably requiring portages, lining rafts down rapids, or simply heaving rafts up and over the blockage. For the well-seasoned and adventurous, however, this provides a spectacular journey filled with class III. Rafters and kayakers should be aware that towards the end of this run, Jarbidge Falls is a class V+ run and should only be run by expert kayakers. A huge, row home-sized boulder blocking half the river signals the beginning of this rapid, access to the river is preferably via 4 wheel drive or ATV. The Big Bend campground is located nearby and is suitable for day-tripping to the river, access is near impossible from other locations in Nevada until about June/July due to snowdrifts across the mountainous access roads, otherwise access is from Idaho. The headwaters of the Jarbidge River are protected as the Jarbidge Wilderness, the Jarbidge River is home to a small population of threatened bull trout. Bull trout inhabit both forks of the Jarbidge River, as well as several tributaries and this small population is on the southern edge of the species range, and is isolated from other populations of bull trout in southern Idaho, increasing their sensitivity to changes in habitat. Population densities were estimated at 10–20 fish per km in 1996, columbia River redband trout also inhabit the river. List of rivers of Idaho List of longest streams of Idaho List of rivers of Nevada List of National Wild and Scenic Rivers
7.
Snake River
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The Snake River is a major river of the greater Pacific Northwest in the United States. At 1,078 miles long, it is the largest tributary of the Columbia River and its drainage basin encompasses parts of six U. S. states, and its average discharge is over 54,000 cubic feet per second. Rugged mountains divided by rolling plains characterize the physiographically diverse watershed of the Snake River, the Snake River Plain was created by a volcanic hotspot which now lies underneath Yellowstone National Park, where the headwaters of the Snake River arise. Two of these flooding events significantly affected the river and its surrounds. More than 11,000 years ago, prehistoric Native Americans lived along the Snake, Salmon from the Pacific Ocean spawned by the millions in the river. These fish were central to the lives of the people along the Snake below Shoshone Falls, by the time Lewis and Clark crossed the Rockies and sighted the valley of a Snake tributary, the Nez Perce and Shoshone were the most powerful peoples in the region. Some tribes adopted use of horses after contact with Europeans, which reshaped their hunting, later explorers and fur trappers further changed and used the resources of the Snake River basin. At one point, a sign made by the Shoshones representing fish was misinterpreted to represent a snake. By the middle 19th century, the Oregon Trail, a trail of which a major portion followed the Snake River, had been established by aspiring settlers and traders. Steamboats and railroads moved agricultural products and minerals along the river throughout the 19th, several of these have been proposed for removal in order to restore some of the rivers once-tremendous salmon runs. Its first 50-mile run through the valley of Jackson Hole, which cuts between the Teton Range and the Continental Divide, there it is also met by the Salt River at the mouth of Star Valley. Southwest of the city of Rexburg, the Snake receives from the right the Henrys Fork, the confluence with the Henrys Fork takes the river southwards through downtown Idaho Falls, rounding the Fort Hall Indian Reservation and into American Falls Reservoir, receiving the Portneuf River. Close to Twin Falls, the Snake approaches the southernmost point in its entire course, after which it starts to flow generally northwest. Shortly after it passes within 30 miles of the Idaho state capital of Boise, there were hundreds of rapids in Hells Canyon, some of which have been stilled by the three dams of the Hells Canyon Hydroelectric Project, Hells Canyon, Oxbow, and Brownlee. The Salmon River, the largest tributary of the Snake River, meets it in one of the most remote areas of its entire course, the confluence of the Snake and Columbia rivers has been submerged in Lake Wallula, the reservoir of McNary Dam. The Columbia River flows about 325 miles further west to the Pacific Ocean, as recently as 165 million years ago, most of western North America was still part of the Pacific Ocean. Even larger lava flows of Columbia River basalts issued over eastern Washington, forming the Columbia Plateau southeast of the Columbia River, separate volcanic activity formed the northwestern portion of the plain, an area far from the path of the hotspot which now lies beneath Yellowstone National Park. At this point, the Snake River watershed was beginning to take shape, the Snake River Plain and the gap between the Sierra Nevada and Cascade Range formed a moisture channel, running as far inland as the headwaters of the Snake River
8.
C. J. Strike Reservoir
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C. J. Strike Reservoir is a reservoir located in southwestern Idaho. Its main recreational features include the C. J. Strike Dam and its 7, 500-acre reservoir and this in turn provides excellent fishing and boating opportunities along with, to a lesser extent camping and hiking. The area is maintained and managed largely by Idaho Power Company, the area is also known for ruts from the Oregon Trail which can still be seen by hiking the area. Http, //fishandgame. idaho. gov/ifwis/Fishingplanner/WaterInfo. aspx. qt=1&ID=26&WID=15428 Due to ignorance of certain individuals other known species have also been found, like all natural resources, continued abuse of the reservoirs ecosystem could have a detrimental effect on future fishing. Http, //www. idahostatesman. com/2009/04/01/717960/walleye-caught-in-idahos-cj-strike. html CJ Strike Reservoir, Bureau of Land Management, Idaho
9.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
10.
National Wild and Scenic Rivers System
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The National Wild and Scenic River is a designation for certain protected areas in the United States. The National Wild and Scenic Rivers Act was an outgrowth of the recommendations of a Presidential commission, among other things, the commission recommended that the nation protect wild rivers and scenic rivers from development that would substantially change their wild or scenic nature. The act was sponsored by Sen. Frank Church and signed into law by President Lyndon B. Johnson on October 2,1968, a river or river section may be designated by the U. S. Congress or the Secretary of the Interior. In 1968, as part of the act, eight rivers were designated as National Wild. As of July 2011,203 rivers, totaling 12,598 miles of river in 38 states and Puerto Rico, have wild and scenic status. By comparison, more than 75,000 large dams across the country have modified at least 600,000 miles, or about 17%, of American rivers. Selected rivers in the United States are preserved for possessing outstandingly remarkable scenic, recreational, geologic, fish and wildlife, historic, cultural, Rivers, or sections of rivers, so designated are preserved in their free-flowing condition and are not dammed or otherwise impeded. National wild and scenic designation essentially vetoes the licensing of new projects on or directly affecting the river. Designation as a wild and scenic river is not the same as a national park designation, however, wild and scenic designation protects the free-flowing nature of rivers in non-federal areas, something the Wilderness Act and other federal designations cannot do. Designation does not alter property rights, federally administered National Wild and Scenic rivers are managed by one or more of the four principal land-managing agencies of the federal government. Of the 156 National Wild and Scenic Rivers, the most are managed by the U. S. Forest Service, thirty-eight are managed under the Bureau of Land Managements National Landscape Conservation System while the U. S. Fish and Wildlife Service manages several rivers in Alaska. State-managed wild and scenic rivers are subject to the same protections as federally administered rivers and these state rivers are added to the National System by the Secretary of the Interior following an application by the governor of the state the river flows through. Wild and scenic rivers are assigned one or more classifications, wild, scenic and these classifications are based on the developmental character of the river on the date of designation. Wild rivers are the most remote and undeveloped while recreational rivers often have access points, roads, railroads. A rivers classification is not related to the value that made it worthy of designation, for instance, recreation may not be an outstanding value on a river with a recreational classification nor scenery on a river classified as scenic. Notably, wild and scenic rivers receive the standard of protection regardless of classification. Nashua River Wild and Scenic River Study Act – proposed a study of the Nashua River in Massachusetts for possible inclusion in the system, list of National Wild and Scenic Rivers Protected areas of the United States National Wild and Scenic Rivers System Wild and Scenic Rivers Act
11.
Tributary
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A tributary or affluent is a stream or river that flows into a larger stream or main stem river or a lake. A tributary does not flow directly into a sea or ocean, tributaries and the main stem river drain the surrounding drainage basin of its surface water and groundwater, leading the water out into an ocean. A confluence, where two or more bodies of water together, usually refers to the joining of tributaries. The opposite to a tributary is a distributary, a river or stream that branches off from, distributaries are most often found in river deltas. Right tributary and left tributary are terms stating the orientation of the relative to the flow of the main stem river. These terms are defined from the perspective of looking downstream, where tributaries have the same name as the river into which they feed, they are called forks. These are typically designated by compass direction, for example, the American River receives flow from its North, Middle, and South forks. The Chicago Rivers North Branch has the East, West, and Middle Fork, the South Branch has its South Fork, forks are sometimes designated as right or left. Here, the handedness is from the point of view of an observer facing upstream, for instance, Steer Creek has a left tributary which is called Right Fork Steer Creek. Tributaries are sometimes listed starting with those nearest to the source of the river, the Strahler Stream Order examines the arrangement of tributaries in a hierarchy of first, second, third, and higher orders, with the first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary, another method is to list tributaries from mouth to source, in the form of a tree structure, stored as a tree data structure
12.
U.S. state
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A U. S. state is a constituent political entity of the United States of America. There are 50 states, which are together in a union with each other. Each state holds administrative jurisdiction over a geographic territory. Due to the shared sovereignty between each state and the government, Americans are citizens of both the federal republic and of the state in which they reside. State citizenship and residency are flexible, and no government approval is required to move between states, except for persons covered by certain types of court orders. States range in population from just under 600,000 to over 39 million, four states use the term commonwealth rather than state in their full official names. States are divided into counties or county-equivalents, which may be assigned some local authority but are not sovereign. County or county-equivalent structure varies widely by state, State governments are allocated power by the people through their individual constitutions. All are grounded in principles, and each provides for a government. States possess a number of powers and rights under the United States Constitution, Constitution has been amended, and the interpretation and application of its provisions have changed. The general tendency has been toward centralization and incorporation, with the government playing a much larger role than it once did. There is a debate over states rights, which concerns the extent and nature of the states powers and sovereignty in relation to the federal government. States and their residents are represented in the federal Congress, a legislature consisting of the Senate. Each state is represented in the Senate by two senators, and is guaranteed at least one Representative in the House, members of the House are elected from single-member districts. Representatives are distributed among the states in proportion to the most recent constitutionally mandated decennial census, the Constitution grants to Congress the authority to admit new states into the Union. Since the establishment of the United States in 1776, the number of states has expanded from the original 13 to 50, alaska and Hawaii are the most recent states admitted, both in 1959. The Constitution is silent on the question of states have the power to secede from the Union. Shortly after the Civil War, the U. S. Supreme Court, in Texas v. White, as a result, while the governments of the various states share many similar features, they often vary greatly with regard to form and substance
13.
Canyon
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A canyon or gorge is a deep cleft between escarpments or cliffs resulting from the erosive activity of a river over geologic timescales. A canyon may also refer to a rift between two peaks, such as those in ranges including the Rocky Mountains, the Alps. Usually a river or stream and erosion carve out such splits between mountains, examples of mountain-type canyons are Provo Canyon in Utah or Yosemite National Park in Californias Sierra Nevada. Canyons within mountains, or gorges that have an opening on one side are called box canyons. Slot canyons are very narrow canyons, often with smooth walls, steep-sided valleys in the seabed of the continental slope underwater are referred to as submarine canyons. Unlike canyons on land, submarine canyons are thought to be formed by turbidity currents, the word canyon is Spanish in origin, with the same meaning. The word canyon is used in North America while the words gorge and ravine are used in Europe and Oceania, though gorge. In the United States, place names generally use canyon in the southwest and gorge in the northeast, in Canada, a gorge is usually narrow while a ravine is more open and often wooded. The military-derived word defile is occasionally used in the United Kingdom, most canyons were formed by a process of long-time erosion from a plateau or table-land level. The cliffs form because harder rock strata that are resistant to erosion, Canyons are much more common in arid than in wet areas because physical weathering has a more localized effect in arid zones. The wind and water from the combine to erode and cut away less resistant materials such as shales. The freezing and expansion of water also serves to help form canyons, water seeps into cracks between the rocks and freezes, pushing the rocks apart and eventually causing large chunks to break off the canyon walls, in a process known as frost wedging. Canyon walls are formed of resistant sandstones or granite. Sometimes large rivers run through canyons as the result of geological uplift. These are called entrenched rivers, because they are unable to alter their course. In the United States, the Colorado River in the Southwest, Canyons often form in areas of limestone rock. As limestone is soluble to an extent, cave systems form in the rock. When these collapse, a canyon is left, as in the Mendip Hills in Somerset and Yorkshire Dales in Yorkshire, England
14.
Lava
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Lava is the molten rock expelled by a volcano during an eruption. The resulting rock after solidification and cooling is called lava. The molten rock is formed in the interior of planets, including Earth. The source of the heat melts the rock within the earth is geothermal energy. When first erupted from a vent, lava is a liquid usually at temperatures from 700 to 1,200 °C. A lava flow is an outpouring of lava, which is created during a non-explosive effusive eruption. When it has stopped moving, lava solidifies to form igneous rock, the term lava flow is commonly shortened to lava. Although lava can be up to 100,000 times more viscous than water, lava can flow great distances before cooling and solidifying because of its thixotropic, explosive eruptions produce a mixture of volcanic ash and other fragments called tephra, rather than lava flows. The word lava comes from Italian, and is derived from the Latin word labes which means a fall or slide. The first use in connection with extruded magma was apparently in an account written by Francesco Serao on the eruption of Vesuvius between May 14 and June 4,1737. Serao described a flow of lava as an analogy to the flow of water. The composition of almost all lava of the Earths crust is dominated by silicate minerals, mostly feldspars, olivine, pyroxenes, amphiboles, micas, igneous rocks, which form lava flows when erupted, can be classified into three chemical types, felsic, intermediate, and mafic. These classes are primarily chemical, however, the chemistry of lava also tends to correlate with the temperature, its viscosity. Felsic or silicic lavas such as rhyolite and dacite typically form lava spines, most silicic lava flows are extremely viscous, and typically fragment as they extrude, producing blocky autobreccias. Felsic magmas can erupt at temperatures as low as 650 to 750 °C, unusually hot rhyolite lavas, however, may flow for distances of many tens of kilometres, such as in the Snake River Plain of the northwestern United States. Intermediate or andesitic lavas are lower in aluminium and silica, and usually somewhat richer in magnesium, intermediate lavas form andesite domes and block lavas, and may occur on steep composite volcanoes, such as in the Andes. Poorer in aluminium and silica than felsic lavas, and also commonly hotter, greater temperatures tend to destroy polymerized bonds within the magma, promoting more fluid behaviour and also a greater tendency to form phenocrysts. Higher iron and magnesium tends to manifest as a darker groundmass, mafic or basaltic lavas are typified by their high ferromagnesian content, and generally erupt at temperatures in excess of 950 °C
15.
Drainage basin
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A drainage basin or catchment area is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. Drainage basins connect into other drainage basins at elevations in a hierarchical pattern, with smaller sub-drainage basins. Other terms used to describe drainage basins are catchment, catchment basin, drainage area, river basin and water basin. In closed drainage basins the water converges to a point inside the basin, known as a sink, which may be a permanent lake. The drainage basin acts as a funnel by collecting all the water within the covered by the basin. Each drainage basin is separated topographically from adjacent basins by a perimeter, drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks, in a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins. Drainage basins of the oceans and seas of the world. Grey areas are endorheic basins that do not drain to the oceans, the following is a list of the major ocean basins, About 48. 7% of the worlds land drains to the Atlantic Ocean. The two major mediterranean seas of the world also flow to the Atlantic, The Caribbean Sea and Gulf of Mexico basin includes most of the U. S. The Mediterranean Sea basin includes much of North Africa, east-central Africa, Southern, Central, and Eastern Europe, Turkey, and the areas of Israel, Lebanon. Just over 13% of the land in the world drains to the Pacific Ocean, the Indian Oceans drainage basin also comprises about 13% of Earths land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, antarctica comprises approximately eight percent of the Earths land. The five largest river basins, from largest to smallest, are the basins of the Amazon, the Río de la Plata, the Congo, the Nile, and the Mississippi. The three rivers that drain the most water, from most to least, are the Amazon, Ganga, endorheic drainage basins are inland basins that do not drain to an ocean. Around 18% of all land drains to endorheic lakes or seas or sinks, the largest of these consists of much of the interior of Asia, which drains into the Caspian Sea, the Aral Sea, and numerous smaller lakes. Some of these, such as the Great Basin, are not single drainage basins but collections of separate, in endorheic bodies of standing water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this is the Dead Sea, drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important
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Jarbidge Mountains
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The Jarbidge Mountains are a mountain range in northern Elko County, Nevada, United States. The central core of the range, including most of the peaks above 10,500 feet, the central Jarbidge Mountains and Marys River Range are also included within the Jarbidge Wilderness. Most of the other sub-ranges west of the core are included within the Mountain City Ranger District. The Salmon River Range is the only sub-range not included within the Humboldt-Toiyabe National Forest, the highest peaks in the range include, Matterhorn Peak 10,838 feet. com Jarbidge Ranger District
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Owyhee Mountains
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The Owyhee Mountains are a mountain range in Owyhee County, Idaho and Malheur County, Oregon. Mahogany Mountain and the volcanic craters of the Lake Owyhee volcanic field are in the Owyhee Mountains of Oregon just east of the Owyhee Reservoir on the Owyhee River. The southeastern end of the range including the old mining area west of Silver City is referred to as the Silver City Range. About 8.3 kilometres west of Silver City is the De Lamar ghost town in Jordan Creek below the mine workings on De Lamar Mountain to the south, the area was active in the late 1880s. In the 1970s mining began again with the development of open pit mines on De Lamar Mountain. Adams, Mildretta Sagebrush Post Offices, A History of the Owyhee Country, Idaho State University Press ISBN 978-0937834138
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Jarbidge Ranger District
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The Jarbidge Ranger District is a 243, 907-acre ranger district within the Humboldt-Toiyabe National Forest. It is located in northern Elko County, Nevada, United States, the town of Jarbidge is contained within the district. The district encompasses the central Jarbidge Mountains and various subsidiary ranges such as the Marys River Range, Fox Creek Range and it also contains the Jarbidge Wilderness. The headwaters of the Jarbidge River, Marys River and Salmon Falls Creek lie within the district, two small lakes, Jarbidge Lake and Emerald Lake, are also located in the district. Elevations range from 6,000 feet in the valleys to the Jarbidge Mountain range high point, Matterhorn Peak, the area provides a wide range of temperature, vegetation, and recreational opportunities for the outdoor enthusiast. Visitors can enjoy quiet campgrounds, hunting, stream fishing, or one of the wilderness areas in the nation. Wildflower viewing is popular, particularly in Copper Basin along the border with the Mountain City Ranger District
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Mountain City Ranger District
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The Mountain City Ranger District is a 450, 000-acre ranger district within the Humboldt-Toiyabe National Forest. It is located in northern Elko County, Nevada, United States, the town of Mountain City is contained within the district. Elevations range from 4,600 feet in the Bruneau Rivers valley to the Independence Mountain range high point, McAfee Peak, the area provides a wide range of temperature, vegetation, and recreational opportunities for the outdoor enthusiast. Visitors can enjoy quiet campgrounds, hunting and stream fishing, wildflower viewing is also popular, particularly in Copper Basin along the border with the Jarbidge Ranger District
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Humboldt-Toiyabe National Forest
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The Humboldt-Toiyabe National Forest is the principal U. S. National Forest in the U. S. state of Nevada, and has a smaller portion in Eastern California. With an area of 6,289,821 acres, it is the largest National Forest of the United States outside of Alaska. HTNF does not resemble most other National Forests in that it has fairly large but non-contiguous sections scattered about most of the state of Nevada. Its 10 ranger districts are scattered across the mountain ranges in Nevada. A part of the forest is in eastern California, in the areas around Bridgeport and Markleeville, the forest lies in 13 counties in Nevada and 6 in California. The counties with the largest amount of forest land are Nye, Elko, and White Pine in Nevada, and Mono County in California, Forest headquarters are located in Sparks, Nevada. It has about 43. 5% of the total area, there are local ranger district offices located in Ely, Elko, Wells, and Winnemucca. It has about 56. 5% of the total area, there are local ranger district offices located in Austin, Bridgeport, Carson City, Las Vegas, and Tonopah
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Snake River Plain
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The Snake River Plain is a geologic feature located primarily within the U. S. state of Idaho. It stretches about 400 miles westward from northwest of the state of Wyoming to the Idaho-Oregon border, the plain is a wide, flat bow-shaped depression and covers about a quarter of Idaho. Three major volcanic buttes dot the plain east of Arco, the largest being Big Southern Butte, most of Idahos major cities are in the Snake River Plain, as is much of its agricultural land. The Snake River Plain can be divided into three sections, western, central, and eastern, the western plain began to form around 11–12 Ma with the eruption of rhyolite lavas and ignimbrites. The western plain is not parallel to North American Plate motion and lies at an angle to the central. Its morphology is similar to other volcanic plateaus such as the Chilcotin Group in south-central British Columbia, the eastern Snake River Plain traces the path of the North American Plate over the Yellowstone hotspot, now centered in Yellowstone National Park. The eastern plain is a depression that cuts across Basin and Range mountain structures. It is underlain almost entirely by basalt erupted from large shield volcanoes, beneath the basalts are rhyolite lavas and ignimbrites that erupted as the lithosphere passed over the hotspot. The central Snake River plain is similar to the plain but differs by having thick sections of interbedded lacustrine and fluvial sediments. Island Park and Yellowstone Calderas formed as the result of enormous rhyolite ignimbrite eruptions, henrys Fork Caldera, measuring 18 miles by 23 miles, may be the largest symmetrical caldera in the world. The caldera formed when a dome of magma built up and then drained away, the center of the dome collapsed, leaving a caldera. Henrys Fork Caldera lies within the older and larger Island Park Caldera, younger volcanoes that erupted after passing over the hotspot covered the plain with young basalt lava flows in places, including Craters of the Moon National Monument. The Snake River Plain has a significant effect on the climate of Yellowstone National Park, over time, the Yellowstone hotspot left a 70-mile wide channel through the Rocky Mountains. This channel is in line with the gap between the Cascade Range and the Sierra Nevada, the result is a moisture channel extending from the Pacific Ocean to Yellowstone. Moisture from the Pacific Ocean streams onshore in the form of clouds, the result is a localized climate on the eastern side of the Rockies that is akin to a climate on the west slope of the Cascades or the northern Sierras. Lost streams of Idaho Snake River Snake River Plain Wilson Butte Cave The Snake River Plain Snake River Plain at Digital Atlas of Idaho
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