1.
Chimborazo
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Chimborazo is a currently inactive stratovolcano in the Cordillera Occidental range of the Andes. Its last known eruption is believed to have occurred around 550 C. E, with a peak elevation of 6,263 m, Chimborazo is the highest mountain in Ecuador. It is the highest peak near the equator, Chimborazo is not the highest mountain by elevation above sea level, but its location along the equatorial bulge makes its summit the farthest point on the Earths surface from the Earths center. Chimborazo is in the Cordillera Occidental of the Andes of central Ecuador,150 km south-southwest of the capital Quito and it is a neighbor to 5,018 m high Carihuairazo. Chimborazos summit rises 2,500 m above the surrounding highlands with a ≈20 km wide base, under clear conditions, the summit of Chimborazo can be seen from the coastal city Guayaquil, nearly 140 km away. The nearest cities are Riobamba, Ambato and Guaranda, Chimborazo is surrounded by the Reserva de Produccion Faunistica Chimborazo, which forms a protected ecosystem to preserve the habitat for the Andes native camelids of vicuña, llama and alpaca. Chimborazo is at the end of the Ecuadorian Volcanic Arc. Chimborazo is in la Avenida de los Volcanes west of the Sanancajas mountain chain, Carihuairazo, Tungurahua, Tulabug, and El Altar are all mountains that neighbor Chimborazo. The closest mountain peak, Carihuairazo, is 5.8 mi from Chimborazo, there are many microclimates near Chimborazo, varying from desert in the Arenal to the humid mountains in the Abraspungo valley. The top of Chimborazo is completely covered by glaciers, with some north-eastern glacier arms flowing down to 4,600 m and its glacier is the source of water for the population of the Bolivar and Chimborazo provinces of Ecuador. As on other glaciated Ecuadorian mountains, Chimborazos glacial ice is mined by locals to be sold in the markets of Guaranda, in earlier days, the people transported ice for cooling uses down to coastal towns such as Babahoyo or Vinces. With an elevation of 6,263 m, Chimborazo is the highest mountain in Ecuador and the Andes north of Peru, it is higher than any more northerly summit in the Americas. Chimborazo is one degree south of the Equator and the Earths diameter at the Equator is greater than at the latitude of Everest, nearly 27. 6° north, with sea level also elevated. Despite being 2,585 m lower in elevation above sea level, however, by the criterion of elevation above sea level, Chimborazo is not even the highest peak of the Andes. Chimborazo is an inactive volcano in Ecuador. Chimborazo is a volcano composed of one volcanic edifice on top of another. Chimborazo shows four summits, Veintimilla, Whymper, Politecnica, the Veintimilla peak is about 6,230 m high. The Whymper peak is the highest point on the mountain at 6,263 meters, the Politecnica peak is 5,820 m high
2.
Ecuador
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Ecuador also includes the Galápagos Islands in the Pacific, about 1,000 kilometres west of the mainland. What is now Ecuador was home to a variety of Amerindian groups that were incorporated into the Inca Empire during the 15th century. The territory was colonized by Spain during the 16th century, achieving independence in 1820 as part of Gran Colombia, Spanish is the official language and is spoken by a majority of the population, though 13 Amerindian languages are also recognized, including Quichua and Shuar. The capital city is Quito, while the largest city is Guayaquil, in reflection of the countrys rich cultural heritage, the historical center of Quito was declared a UNESCO World Heritage Site in 1978. Cuenca, the third-largest city, was declared a World Heritage Site in 1999 as an outstanding example of a planned. Ecuador has an economy that is highly dependent on commodities, namely petroleum. The country is classified as a medium-income country, Ecuador is a democratic presidential republic. The new constitution of 2008 is the first in the world to recognize legally enforceable Rights of Nature, Ecuador is also known for its rich ecology, hosting many endemic plants and animals, such as those of the Galápagos Islands. It is one of 17 megadiverse countries in the world, various peoples had settled in the area of the future Ecuador before the arrival of the Incas. They developed different languages while emerging as unique ethnic groups, even though their languages were unrelated, these groups developed similar groups of cultures, each based in different environments. Over time these groups began to interact and intermingle with each other so that groups of families in one area became one community or tribe, with a similar language and culture. Many civilizations arose in Ecuador, such as the Valdivia Culture and Machalilla Culture on the coast, the Quitus, each civilization developed its own distinctive architecture, pottery, and religious interests. Eventually, through wars and marriage alliances of their leaders, a group of nations formed confederations, one region consolidated under a confederation called the Shyris, which exercised organized trading and bartering between the different regions. Its political and military came under the rule of the Duchicela blood-line. The native confederations that gave them the most problems were deported to distant areas of Peru, Bolivia, similarly, a number of loyal Inca subjects from Peru and Bolivia were brought to Ecuador to prevent rebellion. Thus, the region of highland Ecuador became part of the Inca Empire in 1463 sharing the same language, in contrast, when the Incas made incursions into coastal Ecuador and the eastern Amazon jungles of Ecuador, they found both the environment and indigenous people more hostile. Moreover, when the Incas tried to subdue them, these indigenous people withdrew to the interior, as a result, Inca expansion into the Amazon basin and the Pacific coast of Ecuador was hampered. The indigenous people of the Amazon jungle and coastal Ecuador remained relatively autonomous until the Spanish soldiers, the Amazonian people and the Cayapas of Coastal Ecuador were the only groups to resist Inca and Spanish domination, maintaining their language and culture well into the 21st century
3.
Timothy H. O'Sullivan
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Timothy H. OSullivan was a photographer widely known for his work related to the American Civil War and the Western United States. OSullivans history and personal life remains a mystery for many historians as there is information to work off of. For example, he was born in Ireland and came to New York City two years later with his parents or his parents traveled to New York before he was born. There is no way of finding out which of the two stories is true and we do know that as a teenager, he was employed by Mathew Brady. There is no record of him fighting and he most likely did civilians work for the army such as surveying, and he took photographs in his spare time. After being honorably discharged, he rejoined Bradys team, in July 1862, OSullivan followed the campaign of Maj. Gen. John Popes Northern Virginia Campaign. By joining Alexander Gardners studio, he had his photographs published in the first Civil War photographs collection. In July 1863, he created his most famous photograph, The Harvest of Death, in 1864, following Gen. Ulysses S. Grants trail, he photographed the Siege of Petersburg before briefly heading to North Carolina to document the siege of Fort Fisher. That brought him to the Appomattox Court House, the site of Robert E. Lees surrender in April 1865, from 1867 to 1869, he was the official photographer on the United States Geological Exploration of the Fortieth Parallel under Clarence King. The expedition began at Virginia City, Nevada, where he photographed the mines and his job was to photograph the West to attract settlers. In so doing, he one of the pioneers in the field of geophotography. OSullivans pictures were among the first to record the ruins, Navajo weavers. In contrast to the Asian and Eastern landscape fronts, the matter he focused on was a new concept. It involved taking pictures of nature as an untamed, pre-industrialized land without the use of painting conventions. OSullivan combined science and art, making records of extraordinary beauty. In 1870 he joined a team in Panama to survey for a canal across the isthmus. From 1871 to 1874 he returned to the southwestern United States to join Lt. George M. Wheelers survey west of the 100th meridian west. He faced starvation on the Colorado River when some of the boats capsized
4.
Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
5.
Geology
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Geology is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also refer generally to the study of the features of any terrestrial planet. Geology gives insight into the history of the Earth by providing the evidence for plate tectonics, the evolutionary history of life. Geology also plays a role in engineering and is a major academic discipline. The majority of data comes from research on solid Earth materials. These typically fall into one of two categories, rock and unconsolidated material, the majority of research in geology is associated with the study of rock, as rock provides the primary record of the majority of the geologic history of the Earth. There are three types of rock, igneous, sedimentary, and metamorphic. The rock cycle is an important concept in geology which illustrates the relationships between three types of rock, and magma. When a rock crystallizes from melt, it is an igneous rock, the sedimentary rock can then be subsequently turned into a metamorphic rock due to heat and pressure and is then weathered, eroded, deposited, and lithified, ultimately becoming a sedimentary rock. Sedimentary rock may also be re-eroded and redeposited, and metamorphic rock may also undergo additional metamorphism, all three types of rocks may be re-melted, when this happens, a new magma is formed, from which an igneous rock may once again crystallize. Geologists also study unlithified material which typically comes from more recent deposits and these materials are superficial deposits which lie above the bedrock. Because of this, the study of material is often known as Quaternary geology. This includes the study of sediment and soils, including studies in geomorphology, sedimentology and this theory is supported by several types of observations, including seafloor spreading, and the global distribution of mountain terrain and seismicity. This coupling between rigid plates moving on the surface of the Earth and the mantle is called plate tectonics. The development of plate tectonics provided a basis for many observations of the solid Earth. Long linear regions of geologic features could be explained as plate boundaries, mid-ocean ridges, high regions on the seafloor where hydrothermal vents and volcanoes exist, were explained as divergent boundaries, where two plates move apart. Arcs of volcanoes and earthquakes were explained as convergent boundaries, where one plate subducts under another, transform boundaries, such as the San Andreas Fault system, resulted in widespread powerful earthquakes. Plate tectonics also provided a mechanism for Alfred Wegeners theory of continental drift and they also provided a driving force for crustal deformation, and a new setting for the observations of structural geology
6.
Weather
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Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, weather is understood to mean the weather of Earth. Weather is driven by air pressure, temperature and moisture differences between one place and another and these differences can occur due to the suns angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations, the Hadley Cell, the Ferrel Cell, the Polar Cell, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earths axis is tilted relative to its orbital plane, on Earths surface, temperatures usually range ±40 °C annually. Over thousands of years, changes in Earths orbit can affect the amount and distribution of energy received by the Earth, thus influencing long-term climate. Surface temperature differences in turn cause pressure differences, higher altitudes are cooler than lower altitudes as most atmospheric heating is due to contact with the Earths surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The Earths weather system is a system, as a result. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture, studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiters Great Red Spot, is a storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies, a stars corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind, on Earth, the common weather phenomena include wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes, typhoons, almost all familiar weather phenomena occur in the troposphere. Weather does occur in the stratosphere and can affect weather lower down in the troposphere, Weather occurs primarily due to air pressure, temperature and moisture differences between one place to another. These differences can occur due to the sun angle at any particular spot, in other words, the farther from the tropics one lies, the lower the sun angle is, which causes those locations to be cooler due the spread of the sunlight over a greater surface. The strong temperature contrast between polar and tropical air gives rise to the large scale atmospheric circulation cells and the jet stream, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow
7.
Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
8.
Planet
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The term planet is ancient, with ties to history, astrology, science, mythology, and religion. Several planets in the Solar System can be seen with the naked eye and these were regarded by many early cultures as divine, or as emissaries of deities. As scientific knowledge advanced, human perception of the planets changed, in 2006, the International Astronomical Union officially adopted a resolution defining planets within the Solar System. This definition is controversial because it excludes many objects of mass based on where or what they orbit. The planets were thought by Ptolemy to orbit Earth in deferent, at about the same time, by careful analysis of pre-telescopic observation data collected by Tycho Brahe, Johannes Kepler found the planets orbits were not circular but elliptical. As observational tools improved, astronomers saw that, like Earth, the planets rotated around tilted axes, and some shared such features as ice caps and seasons. Since the dawn of the Space Age, close observation by space probes has found that Earth and the planets share characteristics such as volcanism, hurricanes, tectonics. Planets are generally divided into two types, large low-density giant planets, and smaller rocky terrestrials. Under IAU definitions, there are eight planets in the Solar System, in order of increasing distance from the Sun, they are the four terrestrials, Mercury, Venus, Earth, and Mars, then the four giant planets, Jupiter, Saturn, Uranus, and Neptune. Six of the planets are orbited by one or more natural satellites, several thousands of planets around other stars have been discovered in the Milky Way. e. in the habitable zone. On December 20,2011, the Kepler Space Telescope team reported the discovery of the first Earth-sized extrasolar planets, Kepler-20e and Kepler-20f, orbiting a Sun-like star, Kepler-20. A2012 study, analyzing gravitational microlensing data, estimates an average of at least 1.6 bound planets for every star in the Milky Way, around one in five Sun-like stars is thought to have an Earth-sized planet in its habitable zone. The idea of planets has evolved over its history, from the lights of antiquity to the earthly objects of the scientific age. The concept has expanded to include not only in the Solar System. The ambiguities inherent in defining planets have led to much scientific controversy, the five classical planets, being visible to the naked eye, have been known since ancient times and have had a significant impact on mythology, religious cosmology, and ancient astronomy. In ancient times, astronomers noted how certain lights moved across the sky, as opposed to the fixed stars, ancient Greeks called these lights πλάνητες ἀστέρες or simply πλανῆται, from which todays word planet was derived. In ancient Greece, China, Babylon, and indeed all pre-modern civilizations, it was almost universally believed that Earth was the center of the Universe and that all the planets circled Earth. The first civilization known to have a theory of the planets were the Babylonians
9.
Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
10.
Vegetation
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Vegetation is assemblages of plant species and the ground cover they provide. It is a term, without specific reference to particular taxa, life forms, structure, spatial extent. It is broader than the flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns, all are encompassed by the term vegetation. The vegetation type is defined by characteristic dominant species, or an aspect of the assemblage. The contemporary use of vegetation approximates that of ecologist Frederic Clements term earth cover, Natural vegetation refers to plant life undisturbed by humans in its growth and which is controlled by the climatic conditions of that region. The distinction between vegetation and flora was first made by Jules Thurmann, prior to this, the two terms were used indiscriminately, and still are in some contexts. Augustin de Candolle also made a distinction, but he used the terms station and habitation. Later, the concept of vegetation would influence the usage of the term biome, other concepts similar to vegetation are physiognomy of vegetation and formation. Departing from Linnean taxonomy, Humboldt established a new science, dividing plant geography between taxonomists who studied plants as taxa and geographers who studied plants as vegetation. The physiognomic approach in the study of vegetation is common among biogeographers working on vegetation on a world scale, the concept vegetation type is more ambiguous. For some authors, it includes, besides physiognomy, floristic, furthermore, the phytosociological approach in the study of vegetation relies upon a fundamental unit, the plant association, which is defined upon flora. An influential, clear and simple scheme for types of vegetation was produced by Wagner & von Sydow. Like all the systems, plant communities are temporally and spatially dynamic. Dynamism in vegetation is defined primarily as changes in species composition and/or vegetation structure, temporally, a large number of processes or events can cause change, but for sake of simplicity they can be categorized roughly as either abrupt or gradual. Abrupt changes are referred to as disturbances, these include things like wildfires, high winds, landslides, floods, avalanches. Their causes are external to the community—they are natural processes occurring independently of the natural processes of the community. Such events can change vegetation structure and composition very quickly and for time periods
11.
Sediment
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For sediment in beverages, see dregs. For example, sand and silt can be carried in suspension in water and on reaching the sea be deposited by sedimentation. Sediments are most often transported by water, but also wind, beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of transport and deposition. Glacial moraine deposits and till are ice-transported sediments, sediment can be classified based on its grain size and/or its composition. Sediment size is measured on a log base 2 scale, called the Phi scale, composition of sediment can be measured in terms of, parent rock lithology mineral composition chemical make-up. This leads to an ambiguity in which clay can be used as both a size-range and a composition, sediment is transported based on the strength of the flow that carries it and its own size, volume, density, and shape. Stronger flows will increase the lift and drag on the particle, causing it to rise, rivers and streams carry sediment in their flows. This sediment can be in a variety of locations within the flow and these relationships are shown in the following table for the Rouse number, which is a ratio of sediment fall velocity to upwards velocity. If the upwards velocity is less than the settling velocity, but still high enough for the sediment to move, it will move along the bed as bed load by rolling, sliding. If the upwards velocity is higher than the velocity, the sediment will be transported high in the flow as wash load. As there are generally a range of different particle sizes in the flow, sediment motion can create self-organized structures such as ripples, dunes, antidunes on the river or stream bed. These bedforms are often preserved in rocks and can be used to estimate the direction. Overland flow can erode soil particles and transport them downslope, the erosion associated with overland flow may occur through different methods depending on meteorological and flow conditions. If the initial impact of rain droplets dislodges soil, the phenomenon is called rainsplash erosion, if overland flow is directly responsible for sediment entrainment but does not form gullies, it is called sheet erosion. If the flow and the substrate permit channelization, gullies may form, glaciers carry a wide range of sediment sizes, and deposit it in moraines. The overall balance between sediment in transport and sediment being deposited on the bed is given by the Exner equation and this expression states that the rate of increase in bed elevation due to deposition is proportional to the amount of sediment that falls out of the flow. This can be localized, and simply due to obstacles, examples are scour holes behind boulders, where flow accelerates
12.
Desert
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A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to the processes of denudation, about one third of the land surface of the world is arid or semi-arid. This includes much of the regions where little precipitation occurs. Deserts can be classified by the amount of precipitation falls, by the temperature that prevails. Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces, although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter and the resulting fragments and this picks up particles of sand and dust and wafts them aloft in sand or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface, rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes, other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones. These areas are known as desert pavements and little further erosion takes place, other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate, there may be underground sources of water in the form of springs and seepages from aquifers. Where these are found, oases can occur, plants and animals living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, some annual plants germinate, bloom and die in the course of a few weeks after rainfall while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the heat of the day and they tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine. Some animals remain in a state of dormancy for long periods and they then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and the surrounding lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, the cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Many trade routes have been forged across deserts, especially across the Sahara Desert, large numbers of slaves were also taken northwards across the Sahara
13.
Greek god
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The following is a list of gods, goddesses and many other divine and semi-divine figures from Ancient Greek mythology and Ancient Greek religion. The Greeks created images of their deities for many purposes, a temple would house the statue of a god or goddess, or multiple deities, and might be decorated with relief scenes depicting myths. Divine images were common on coins, drinking cups and other vessels were painted with scenes from Greek myths. The Titans and Titanesses are depicted in Greek art less commonly than the Olympians
14.
Aeolus
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Aeolus, a name shared by three mythical characters, was the ruler of the winds in Greek mythology. These three personages are often difficult to tell apart, and even the ancient mythographers appear to have been perplexed about which Aeolus was which, Diodorus Siculus made an attempt to define each of these three, and his opinion is followed here. All three men named Aeolus appear to be connected genealogically, although the relationship, especially regarding the second. This Aeolus was son of Hellen and the nymph Orseis, described as the ruler of Aeolia and held to be the founder of the Aeolic branch of the Greek nation, this Aeolus married Enarete, daughter of Deimachus. Aeolus and Enarete had many children, although the precise number, other sons included Deioneus, Perieres, Cercaphas and perhaps Magnes and Aethlius. Another son is named Mimas, who provides a link to the third Aeolus in a genealogy that seems very contrived, calyce, Peisidice, Perimede and Alcyone were counted among the daughters of Aeolus and Enarete. This Aeolus also had a daughter named Arne, begotten on Melanippe. This Arne became the mother of the second Aeolus, by the god Poseidon and this Aeolus was a son of Poseidon by Arne, daughter of Aeolus. He had a brother named Boeotus. Arne confessed to her father that she was with child by the god Poseidon, her father, however, did not believe her, and handed her over to a man named Metapontus, King of Icaria. When Bœotus and Aeolus were born, they were raised by Metapontus, although his home has been traditionally identified as one of the Aeolian Islands, near Sicily, an alternative location has been suggested at Gramvousa off the northwest coast of Crete. Aeolus had six sons and six daughters, whom in Homer he wed to one another, other late accounts claim that Macareus had a daughter named Amphissa, beloved by Apollo. This Aeolus is most frequently conflated with Aeolus, the son of Poseidon and it is difficult to differentiate this Aeolus from the second Aeolus, as their identities seem to have been merged by many ancient writers. The father of this third Aeolus is given as Hippotes, son of Mimas, according to some accounts, Hippotes married the same Melanippe who was the mother of Arne. This Aeolus lived on the island of Aeolia and was visited by Odysseus. He gave hospitality for a month and provided for a west wind to carry them home and he also provided a gift of a bag containing all winds but the west, which Odysseuss crew members unwittingly opened just before they were to reach Ithaca. Unfortunately, they were back to Aeolia, where Aeolus refused to provide any further help, because he believed that their short. This Aeolus was perceived by post-Homeric authors as a god, rather than as a mortal, like the previous, this Aeolus was said to have had twelve children - six sons and six daughters
15.
Dust
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Dust is fine particles of matter. It generally consists of particles in the atmosphere that come from sources such as soil, dust lifted by weather, volcanic eruptions. House dust mites are present indoors wherever humans live, positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead skin cells. They and their feces and other allergens they produce are major constituents of house dust and they are generally found on the floor and other surfaces until disturbed. It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air, Dust mites are a nesting species that prefers a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets and their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body. House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing. Atmospheric or wind-borne dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, Dust in the atmosphere is produced by saltation and sandblasting of sand-sized grains, and it is transported through the troposphere. This airborne dust is considered an aerosol and once in the atmosphere, saharan dust in particular can be transported and deposited as far as the Caribbean and the Amazon basin, and may affect air temperatures, cause ocean cooling, and alter rainfall amounts. Dust in the Middle East has been a historic phenomenon, recently, because of climate change and the escalating process of desertification, the problem has worsened dramatically. As a multi-factor phenomenon, there is not yet a consensus on the sources or potential solutions to the problem. In Iran, the dust is already affecting more than 5 million people directly, in the province of Khuzestan it has led to the severe reduction of air quality. The amount of pollutants in the air has surpassed more than 50 times the normal level several times in a year, recently, initiatives such as Project-Dust have been established to directly study the Middle Eastern dust. Dust kicked up by vehicles traveling on roads may make up 33% of air pollution, road dust consists of deposits of vehicle exhausts and industrial exhausts, particles from tire and brake wear, dust from paved roads or potholes, and dust from construction sites. Road dust is a significant source contributing to the generation and release of particulate matter into the atmosphere. Control of road dust is a significant challenge in urban areas, road dust may be suppressed by mechanical methods like street sweeper vehicles equipped with vacuum cleaners, vegetable oil sprays, or with water sprayers. Improvements in automotive engineering have reduced the amount of PM10s produced by road traffic, coal dust is responsible for the lung disease known as pneumoconiosis, including black lung disease that occurs among coal miners
16.
Altiplano
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The Altiplano, Collao, Andean Plateau or Bolivian Plateau, in west-central South America, is the area where the Andes are the widest. It is the most extensive area of high plateau on Earth outside Tibet, the bulk of the Altiplano lies in Bolivia, but its northern parts lie in Peru, and its southern parts lie in Chile and Argentina. The plateau hosts several cities of three nations, including El Alto, La Paz, Oruro, and Puno. The northeastern Altiplano is more humid than the southwestern area, the latter area has several salares, or salt flats, due to its aridity. At the Bolivia–Peru border lies Lake Titicaca, the largest lake in South America, South of that in Bolivia was Lake Poopó, which was declared dried up and defunct as of December 2015. It is unclear if this second-largest lake in Bolivia can be revitalized, the Altiplano was the site of several pre-Columbian cultures, including the Chiripa, Tiawanaku and the Inca Empire. Spain conquered the region in the 16th century, major economic activities in the Altiplano include mining, llama and vicuña herding, and services in the cities. The Altiplano is an area of inland drainage lying in the central Andes, occupying parts of northern Chile and Argentina, western Bolivia and its height averages about 3,750 meters, slightly less than that of the Tibetan Plateau. The Atacama Desert, one of the driest areas on the planet, lies to the southwest of the Altiplano, the Altiplano is noted for hypoxic air caused by very high elevation. At various times during the Pleistocene epoch, both the southern and northern Altiplano were covered by vast pluvial lakes, remnants are Lake Titicaca, straddling the Peru–Bolivia border, and Poopó, a salt lake that extends south of Oruro, Bolivia. Salar de Uyuni, locally known as Salar de Tunupa, scientists classify the latter as commencing at an elevation of approximately 4,500 meters. Alternate names used in place of altiplano in this context include puna, the diurnal cycle of temperature is very wide, with maximum temperatures in the order of 12 to 24 °C and the minimum in the order of -20 to 10 °C. The coldest temperatures occur in the portion of the Altiplano during the months of June and July. The seasonal cycle of rainfall is marked, with the rainy season concentrated between December and March, the rest of the year tends to be very dry, cool, windy and sunny. Snowfall may happen between April and September, especially to the north, but it is not very common, such weaknesses would cause the partition of tectonic deformation and uplift into the eastern and western cordillera, leaving the necessary space for the formation of the altiplano basin. Altiplano - Where Bolivia meets the sky
17.
Bolivia
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Bolivia, officially known as the Plurinational State of Bolivia, is a landlocked country located in western-central South America. It is bordered to the north and east by Brazil, to the southeast by Paraguay, to the south by Argentina, to the southwest by Chile, and to the northwest by Peru. One-third of the country is the Andean mountain range, with one of its largest cities and principal economic centers, El Alto, Bolivia is one of two landlocked countries that lie outside Afro-Eurasia. Bolivia is geographically the largest landlocked country in the Americas, but remains a small country in economic. Before Spanish colonization, the Andean region of Bolivia was part of the Inca Empire, Spanish conquistadors arriving from Cuzco and Asunción took control of the region in the 16th century. During the Spanish colonial period Bolivia was administered by the Royal Audiencia of Charcas, spain built its empire in great part upon the silver that was extracted from Bolivias mines. After the first call for independence in 1809,16 years of war followed before the establishment of the Republic, named for Simón Bolívar, on 6 August 1825. Since independence, Bolivia has endured periods of political and economic instability, including the loss of peripheral territories to its neighbors, such as Acre. The countrys population, estimated at 11 million, is multiethnic, including Amerindians, Mestizos, the racial and social segregation that arose from Spanish colonialism has continued to the modern era. Spanish is the official and predominant language, although 36 indigenous languages also have official status, of which the most commonly spoken are Guarani, Aymara, modern Bolivia is constitutionally a unitary state, divided into nine departments. Its geography varies from the peaks of the Andes in the West, to the Eastern Lowlands and it is a developing country, with a medium ranking in the Human Development Index and a poverty level of 53 percent. Its main economic activities include agriculture, forestry, fishing, mining, and manufacturing such as textiles, clothing, refined metals. Bolivia is very wealthy in minerals, especially tin, Bolivia is named after Simón Bolívar, a leader in the Spanish American wars of independence. Sucre opted to create a new nation and, with local support. The original name was Republic of Bolívar, some days later, congressman Manuel Martín Cruz proposed, If from Romulus comes Rome, then from Bolívar comes Bolivia. The name was approved by the Republic on 3 October 1825, the region now known as Bolivia had been occupied for over 2,500 years when the Aymara arrived. However, present-day Aymara associate themselves with the ancient civilization of the Tiwanaku culture which had its capital at Tiwanaku, the capital city of Tiwanaku dates from as early as 1500 BC when it was a small, agriculturally based village. The community grew to urban proportions between AD600 and AD800, becoming an important regional power in the southern Andes
18.
Kelso Dunes
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Kelso Dunes, also known as the Kelso Dune Field, is the largest field of eolian sand deposits in the Mojave Desert. The region is protected by the Mojave National Preserve and is located near the town of Baker, San Bernardino County, California, the dune field covers 45 square miles and includes migrating dunes, vegetation-stabilized dunes, sand sheets, and sand ramps. The tallest dunes rise up to 650 feet above the surrounding terrain, the dunes are composed predominantly of light-colored quartz and feldspar, most likely eroded from the granitics of the San Bernardino Mountains to the southwest. Magnetite and amphibole can also be found, often accumulating at the dune crests, Kelso Dunes represent part of a much larger sand transport system, which includes the nearby Devils Playground region. The composition and morphology of the sand grains indicate that most originated from the Mojave River sink near Afton Canyon, the sand has accumulated at the southeastern end of the Soda Lake-Kelso basin, where the Granite Mountains and Providence Mountains form a barrier to prevailing winds. At present, only the area around the Mojave River sink, the Kelso Dunes are composed of five stacked sets of dunes, each set corresponding to a period of climate change over the last 25,000 years. During dry climate episodes, a decrease in stabilizing vegetation exposed surface sand to wind erosion, however, once the sand was emplaced, vegetation began to grow, locking much of it into place. The Kelso Dunes are also notable for the known as singing sand. Enthusiasts sometimes climb to the top of the dunes and slide down slowly and this effect has also been noted at the Eureka Dunes in California, Sand Mountain in Nevada, and the Booming Dunes in the Namib Desert of Africa. The booming is much more pronounced when the dunes are extremely dry, Kelso Dunes are closed to off-road vehicles, but are open to hikers. The trailhead is at the end of a graded dirt road splitting from Kelbaker Road. This road can be accessed from both Interstate 15 and Interstate 40, the dunes themselves lie just southwest of the Kelso ghost town and the Parks Visitor Center located in the historic Kelso Depot. Like many southern California dune systems, the Kelso dunes have a number of animal species. The list includes at least ten species of insects, such as the Kelso giant sand treader cricket, the Kelso Jerusalem cricket, Rhaphiomidas tarsalis, although not strictly endemic, several plant and reptile species are rare outside of these dunes. One example is the Mojave fringe-toed lizard, which is specialized in its ability to swim under sand, Kelso, California Kelso Wash Amboy Crater Official Mojave National Preserve website Kelso Depot Visitors Center Photo tour of Mojave National Preserve, from USGS Afton Canyon Natural Area website
19.
Mojave Desert
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The Mojave Desert is an arid rain-shadow desert and the driest desert in North America. It is located in the southwestern United States, primarily within southeastern California and southern Nevada, very small areas also extend into Utah and Arizona. The central part of the desert is sparsely populated, while its peripheries support large communities such as Las Vegas, Lancaster, Palmdale, Victorville, the Mojave Desert is bordered by the Great Basin Desert to its north and the Sonoran Desert to its south and east. Topographical boundaries include the Tehachapi Mountains to the west, and the San Gabriel Mountains, the mountain boundaries are distinct because they are outlined by the two largest faults in California – the San Andreas and Garlock faults. The Mojave Desert displays typical basin and range topography and it occupies less than 50,000 sq mi, making it the smallest of the North American deserts. The Mojave Desert is often referred to as the desert, in contrast to the low desert. However, the Mojave Desert is generally lower than the Great Basin Desert to the north, the spelling Mojave originates from the Spanish language while the spelling Mohave comes from modern English. The Mojave Desert receives less than 13 in of rain a year and is generally between 2,000 and 5,000 feet in elevation, zion National Park in Utah lies at the junction of the Mojave, the Great Basin Desert, and the Colorado Plateau. Despite its aridity, the Mojave has long been a center of production, fed by irrigation coming from groundwater. The Mojave is a desert of temperature extremes and two distinct seasons, winter months bring comfortable daytime temperatures, which dip precipitously to around 20 °F on valley floors, and below 0 °F at higher elevations. Storms moving from the Pacific Northwest can bring rain and in places even snow. More often, the shadow created by the Sierra Nevada as well as mountain ranges within the desert such as the Spring Mountains, bring only clouds. By early June, it is rare for another Pacific storm to have a significant impact on the regions weather, summer weather is dominated by heat. Temperatures on valley floors can soar above 120 °F and above 130 °F at the lowest elevations, low humidity, high temperatures, and low pressure, draw in moisture from the Gulf of Mexico creating thunderstorms across the desert southwest known as the North American monsoon. Autumn is generally pleasant, with one to two Pacific storm systems creating regional rain events, october is one of the driest and sunniest months in the Mojave, and temperatures usually remain between 70 °F and 90 °F on the valley floors. After temperature, wind is the most significant weather phenomenon in the Mojave, during the June Gloom, cooler air can be pushed out into the desert from Southern California. In Santa Ana wind events, hot air from the desert blows out into the Los Angeles basin, wind farms in these areas generate power from these winds. The other major factor in the region is elevation
20.
Navajo Sandstone
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Navajo Sandstone frequently overlies and interfingers with the Kayenta Formation of the Glen Canyon Group. Together, these formations can result in immense vertical cliffs of up to 2,200 feet, atop the cliffs, Navajo Sandstone often appears as massive rounded domes and bluffs that are generally white in color. Navajo Sandstone frequently occurs as spectacular cliffs, cuestas, domes and it can be distinguished from adjacent Jurassic sandstones by its white to light pink color, meter-scale cross-bedding, and distinctive rounded weathering. The wide range of colors exhibited by the Navajo Sandstone reflect a history of alteration by groundwater and other subsurface fluids over the last 190 million years. The iron in these strata originally arrived via the erosion of iron-bearing silicate minerals, initially, this iron accumulated as iron-oxide coatings, which formed slowly after the sand had been deposited. Later, after having been buried, reducing fluids composed of water. The dissolution of the iron coatings by the reducing fluids bleached large volumes of the Navajo Sandstone a brilliant white, reducing fluids transported the iron in solution until they mixed with oxidizing groundwater. Where the oxidizing and reducing fluids mixed, the iron precipitated within the Navajo Sandstone, the precipitation of iron oxides also formed laminea, corrugated layers, columns, and pipes of ironstone within the Navajo Sandstone. The age of the Navajo Sandstone is somewhat controversial and it may originate from the Late Triassic but is at least as young as the Early Jurassic stages Pliensbachian and Toarcian. There is no type locality of the name and it was simply named for the Navajo Country of the southwestern United States. The two major subunits of the Navajo are the Lamb Point Tongue and the Shurtz Sandstone Tongue, the Navajo Sandstone was originally named as the uppermost formation of the La Plata Group by Gregory and Stone in 1917. Baker reassigned it as the formation of Glen Canyon Group in 1936. Its age was modified by Lewis and others in 1961, the name was originally not used in northwest Colorado and northeast Utah, where the name Glen Canyon Sandstone was preferred. Its age was modified again by Padian in 1989, the sandstone was deposited in an arid erg on the Western portion of the Supercontinent Pangaea. This region was affected by monsoons that came about each winter when cooler winds. Theropod tracks are located in Arizona, Colorado, and Utah. Ornithischian tracks located in Arizona, USA, the Navajo Sandstone is also well known among rockhounds for its hundreds of thousands of iron oxide concretions. They are believed to represent an extension of Hopi Native American traditions regarding ancestor worship, informally, they are called Moqui marbles after the local proposed Moqui Native American tribe
21.
Moab, Utah
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Moab is a city on the southern edge of Grand County in eastern Utah in the western United States. The population was 5,046 at the 2010 census, and it is the county seat and largest city in Grand County. Moab attracts a number of tourists every year, mostly visitors to the nearby Arches. The town is a base for mountain bikers who ride the extensive network of trails including the Slickrock Trail. The Biblical name Moab refers to an area of land located on the side of the Jordan River. Some historians believe the city in Utah came to use this name because of William Pierce, the first postmaster, believing that the biblical Moab, however, others believe the name has Paiute origins, referring to the word moapa, meaning mosquito. Some of the early residents attempted to change the citys name, because in the Christian Bible. One petition in 1890 had 59 signatures and requested a change to Vina. Another effort attempted to change the name to Uvadalia, during the period between 1829 and the early 1850s, the area around what is now Moab served as the Colorado River crossing along the Old Spanish Trail. Latter-day Saint settlers attempted to establish a fort at the river crossing called the Elk Mountain Mission in April 1855 to trade with travellers attempting to cross the river. Forty men were called on this mission, there were repeated Indian attacks, including one on September 23,1855, in which James Hunt, companion to Peter Stubbs, was shot and killed by a Native American. After this last attack, the fort was abandoned, a new round of settlers established a permanent settlement in 1878. Moab was incorporated as a town on December 20,1902, in 1883 the Denver and Rio Grande Western Railroad main line was constructed across eastern Utah. The rail line did not pass through Moab, instead passing through the towns of Thompson Springs, later, other places to cross the Colorado were constructed, such as Lees Ferry, Navajo Bridge and Boulder Dam. These changes shifted the routes away from Moab. Moab farmers and merchants had to adapt from trading with passing travelers to shipping their goods to distant markets, soon Moabs origins as one of the few natural crossings of the Colorado River were forgotten. Nevertheless, the U. S. military deemed the bridge over the Colorado River at Moab important enough to place it under guard as late as World War II. On January 11,1943, the sixteen men who had initiated the protests were transferred to Moab from the town jails where they were booked after the riot
22.
Turbulence
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Turbulence or turbulent flow is a flow regime in fluid dynamics characterized by chaotic changes in pressure and flow velocity. It is in contrast to a flow regime, which occurs when a fluid flows in parallel layers. Turbulence is caused by kinetic energy in parts of a fluid flow. For this reason turbulence is easier to create in low viscosity fluids, in general terms, in turbulent flow, unsteady vortices appear of many sizes which interact with each other, consequently drag due to friction effects increases. This would increase the energy needed to pump fluid through a pipe, however this effect can also be exploited by such as aerodynamic spoilers on aircraft, which deliberately spoil the laminar flow to increase drag and reduce lift. The onset of turbulence can be predicted by a constant called the Reynolds number. However, turbulence has long resisted detailed physical analysis, and the interactions within turbulence creates a complex situation. Richard Feynman has described turbulence as the most important unsolved problem of classical physics, smoke rising from a cigarette is mostly turbulent flow. However, for the first few centimeters the flow is laminar, the smoke plume becomes turbulent as its Reynolds number increases, due to its flow velocity and characteristic length increasing. If the golf ball were smooth, the boundary layer flow over the front of the sphere would be laminar at typical conditions. However, the layer would separate early, as the pressure gradient switched from favorable to unfavorable. To prevent this happening, the surface is dimpled to perturb the boundary layer. This results in higher skin friction, but moves the point of boundary layer separation further along, resulting in form drag. The flow conditions in industrial equipment and machines. The external flow over all kind of such as cars, airplanes, ships. The motions of matter in stellar atmospheres, a jet exhausting from a nozzle into a quiescent fluid. As the flow emerges into this external fluid, shear layers originating at the lips of the nozzle are created and these layers separate the fast moving jet from the external fluid, and at a certain critical Reynolds number they become unstable and break down to turbulence. Biologically generated turbulence resulting from swimming animals affects ocean mixing, snow fences work by inducing turbulence in the wind, forcing it to drop much of its snow load near the fence
23.
Ventifact
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A ventifact is a rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals. Ventifacts can be abraded to eye-catching natural sculptures such as the features of the White Desert near Farafra oasis in Egypt. In moderately tall, isolated rock outcrops, mushroom shaped pillars of rock may form as the outcrop is eroded by saltating sand grains and this occurs because, even in strong winds, sand grains cant be continuously held in the air. Instead, the bounce along the ground, rarely reaching higher than a few feet above the earth. Over time, the sand grains can erode the lower portions of a ventifact. The results can be fantastic stone mushrooms, individual stones, such as those forming desert pavement, are often found with grooved, etched, or polished surfaces where these same wind-driven processes have slowly worn away the rock. Stones with a number of wind facets have names reflecting this number. When ancient ventifacts are preserved without being moved or disturbed, they may serve as a paleo-wind indicators, the wind direction at the time the ventifact formed will be parallel to grooves or striations cut in the rock. An example of a Martian ventifact was named Jake Matijevic, by analyzing its shape, it was possible to reconstruct the main wind direction which sculpted the rock. Arkenu structures Blowout Dune Yardang The Bibliography of Aeolian Research
24.
Abrasive blasting
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A pressurized fluid, typically compressed air, or a centrifugal wheel is used to propel the blasting material. The first abrasive blasting process was patented by Benjamin Chew Tilghman on 18 October 1870, there are several variants of the process, using various media, some are highly abrasive, whereas others are milder. The most abrasive are shot blasting and sandblasting, moderately abrasive variants include glass bead blasting and media blasting with ground-up plastic stock or walnut shells and corncobs. In addition, there are alternatives that are barely abrasive or nonabrasive, such as ice blasting and dry-ice blasting. One of the pioneers of the wet abrasive process was Norman Ashworth who found the advantages of using a wet process a strong alternative to sandblasting—which is banned in many countries. g. Removal of asbestos, radioactive, or other products from components. The process is available in all formats including hand cabinets, walk-in booths, automated production machinery. Process speeds can be as fast as conventional dry sand blasting when using the equivalent size, however the presence of water between the media and the substrate being processed creates a lubricating cushion that can protect both the media and the surface from excess damage. This has the advantage of lowering media breakdown rates and preventing impregnation of foreign materials into the surface. Subsequent coating or bonding operations are always better after wet blasting than dry blasting because of the levels achieved. The lack of surface recontamination also allows the use of equipment for multiple blasting operations—e. g. Stainless steel and carbon steel items can be processed in the equipment with the same media without problems. Bead blasting is the process of removing surface deposits by applying fine glass beads at a high pressure without damaging the surface and it is used to clean calcium deposits from pool tiles or any other surfaces, remove embedded fungus, and brighten grout color. It is also used in auto body work to remove paint, in removing paint for auto body work, bead blasting is preferred over sand blasting, as sand blasting tends to invite rust formation under re-painted surfaces. Its additionally used in cleaning mineral specimens, most of which have a Mohs hardness of 7 or less, in wheel blasting, a spinning wheel propels the abrasive against an object. It is typically categorized as an airless blasting operation because there is no propellant used, a wheel machine is a high-power, high-efficiency blasting operation with recyclable abrasive. Specialized wheel blast machines propel plastic abrasive in a cryogenic chamber, the size of the wheel blast machine, and the number and power of the wheels vary considerably depending on the parts to be blasted as well as on the expected result and efficiency. The first blast wheel was patented by Wheelabrator in 1932, hydro-blasting, commonly known as water blasting, is commonly used because it usually requires only one operator
25.
Desert pavement
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A desert pavement, also called reg, serir, gibber, or saï is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size. Desert varnish collects on the surface rocks over time. Geologists debate the mechanics of pavement formation and their age, several theories have been proposed for the formation of desert pavements. A common theory suggests they form through the removal of sand, dust and other fine-grained material by the wind and intermittent rain. The removal of particles by wind does not continue indefinitely, because once the pavement forms. The small particles collect underneath the pavement surface, forming a vesicular A soil horizon, a newer theory of pavement formation comes from studies of places such as Cima Dome, in the Mojave Desert of California, by Stephen Wells and his coworkers. At Cima Dome, geologically recent lava flows are covered by younger layers, with desert pavement on top of them. The soil has built up, not blown away, yet the stones remain on top. There are no stones in the soil, not even gravel, researchers can determine how many years a stone has been exposed on the ground. Wells used a method based on cosmogenic helium-3, which forms by cosmic ray bombardment at the ground surface, helium-3 is retained inside grains of olivine and pyroxene in the lava flows, building up with exposure time. The helium-3 dates show that the stones in the desert pavement at Cima Dome have all been at the surface the same amount of time as the solid lava flows right next to them. He wrote in a July 1995 article in Geology, that he concluded, while the stones remain on the surface due to heave, deposition of windblown dust must build up the soil beneath that pavement. For the geologist, this means that some desert pavements preserve a long history of dust deposition beneath them. The dust is a record of ancient climate, just as it is on the sea floor. Desert pavement surfaces are coated with desert varnish, a dark brown. In the USA a famous example can be found on Newspaper Rock in southeastern Utah, Desert varnish is a thin coating of manganese, iron and clays on the surface of sun-baked boulders. It is formed by colonies of bacteria living on the surface for thousands of years. Desert varnish is also prevalent in the Mojave desert and Great Basin geomorphic province, stony deserts may be known by different names according to the region
26.
Mantle (geology)
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The mantle is a layer inside a terrestrial planet and some other rocky planetary bodies. For a mantle to form, the body must be large enough to have undergone the process of planetary differentiation by density. The mantle surrounds the planetary core, the mantle is surrounded by the crust. The terrestrial planets, the Moon, two of Jupiters moons and the asteroid Vesta each have a made of silicate rock. Interpretation of spacecraft data suggests that at least two moons of Jupiter, as well as Titan and Triton each have a mantle made of ice or other solid volatile substances. The interior of Earth, similar to the terrestrial planets, is divided into layers of different composition. The mantle is a layer between the crust and the outer core, Earths mantle is a silicate rocky shell with an average thickness of 2,886 kilometres. The mantle makes up about 84% of Earths volume and it is predominantly solid but in geological time it behaves as a very viscous fluid. The mantle encloses the hot core rich in iron and nickel, past episodes of melting and volcanism at the shallower levels of the mantle have produced a thin crust of crystallized melt products near the surface. A thin crust, the part of the lithosphere, surrounds the mantle and is about 5 to 75 km thick. In some places under the ocean the mantle is exposed on the surface of Earth. The mantle is divided into sections which are based upon results from seismology and these layers are the following, the upper mantle, the transition zone, the lower mantle, and anomalous core–mantle boundary with a variable thickness. The uppermost mantle plus overlying crust are relatively rigid and form the lithosphere, below the lithosphere the upper mantle becomes notably more plastic. In some regions below the lithosphere, the shear velocity is reduced. Inge Lehmann discovered a seismic discontinuity at about 220 km depth, although this discontinuity has been found in other studies, the transition zone is an area of great complexity, it physically separates the upper and lower mantle. Very little is known about the lower mantle apart from that it appears to be relatively seismically homogeneous, the D layer at the core–mantle boundary separates the mantle from the core. A principal source of the heat that drives plate tectonics is the decay of uranium, thorium. The mantle differs substantially from the crust in its properties as the direct consequence of the difference in composition
27.
Desert varnish
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Desert varnish or rock varnish is an orange-yellow to black coating found on exposed rock surfaces in arid environments. Desert varnish is usually around one micrometer thick and represents nanometer-scale layering, Rock rust and desert patina are other terms which are also used for the condition, but less often. Desert varnish forms only on physically stable rock surfaces that are no subject to frequent precipitation. The varnish is composed of particles of clay along with iron. There is also a host of elements and almost always some organic matter. The color of the varnish varies from shades of brown to black and it has been suggested that desert varnish should be investigated as a potential candidate for a shadow biosphere. Originally scientists thought that the varnish was made from substances drawn out of the rocks it coats, microscopic and microchemical observations, however, show that a major part of varnish is clay, which could only arrive by wind. Clay, then, acts as a substrate to catch additional substances that chemically react together when the rock reaches high temperatures in the desert sun, wetting by dew is also important in the process. An important characteristic of desert varnish is that it has an unusually high concentration of manganese. Manganese is relatively rare in the Earths crust, making up only 0. 12% of its weight, in black desert varnish, however, manganese is 50 to 60 times more abundant. One proposal for a mechanism of desert varnish formation is that it is caused by manganese-oxidizing microbes which are common in environments poor in organic nutrients, a micro-environment pH above 7.5 is inhospitable for manganese-concentrating microbes. In such conditions, orange varnishes develop, poor in manganese, however, some Native American peoples created petroglyphs by scraping or chipping away the dark varnish to expose the lighter rock beneath. Desert varnish often obscures the identity of the rock, and different rocks have varying abilities to accept. Limestones, for example, typically do not have varnish because they are too water-soluble, shiny, dense and black varnishes form on basalt, fine quartzites and metamorphosed shales due to these rocks relatively high resistance to weathering. Aeolian processes Manganite Shadow biosphere Desert pavement Desert Varnish Rock Varnish, An Internet Primer for Rock Art Research by Ronald I
28.
Manganese
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Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as an element in nature, it is often found in minerals in combination with iron. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels, by the mid-18th century, Swedish chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite contained a new element, johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. Manganese phosphating is used for rust and corrosion prevention on steel, ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers, Manganese dioxide is used as the cathode material in zinc-carbon and alkaline batteries. In biology, manganese ions function as cofactors for a variety of enzymes with many functions. Manganese enzymes are essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the complex of photosynthetic plants. The element is a trace mineral for all known living organisms but is a neurotoxin. In larger amounts, and apparently with far greater effectiveness through inhalation, Manganese is a silvery-gray metal that resembles iron. It is hard and very brittle, difficult to fuse, Manganese metal and its common ions are paramagnetic. Manganese tarnishes slowly in air and oxidizes like iron in water containing dissolved oxygen, naturally occurring manganese is composed of one stable isotope, 55Mn. Eighteen radioisotopes have been isolated and described, the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days. All of the radioactive isotopes have half-lives of less than three hours, and the majority of less than one minute. Manganese also has three meta states, Manganese is part of the iron group of elements, which are thought to be synthesized in large stars shortly before the supernova explosion. 53Mn decays to 53Cr with a half-life of 3.7 million years, because of its relatively short half-life, 53Mn is relatively rare, produced by cosmic rays impact on iron. Manganese isotopic contents are combined with chromium isotopic contents and have found application in isotope geology
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Iron oxide
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Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides, common rust is a form of iron oxide. Iron oxides are used as inexpensive, durable pigments in paints, coatings. Colors commonly available are in the end of the yellow/orange/red/brown/black range. When used as a coloring, it has E number E172. Limonite Iron oxide nanoparticles List of inorganic pigments Information from Nano-Oxides, http, //chemed. chem. purdue. edu/demos/demosheets/12.3. html http, //minerals. usgs. gov/minerals/pubs/commodity/iron_oxide/ CDC - NIOSH Pocket Guide to Chemical Hazards de
30.
Hydroxide
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Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a covalent bond and it is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, the hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical, a hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation, making the parent compound an acid. The corresponding electrically neutral compound •HO is the hydroxyl radical, the corresponding covalently-bound group –OH of atoms is the hydroxyl group. Hydroxide ion and hydroxyl group are nucleophiles and can act as a catalyst in organic chemistry, many inorganic substances which bear the word hydroxide in their names are not ionic compounds of the hydroxide ion, but covalent compounds which contain hydroxyl groups. The pH of a solution is equal to the decimal cologarithm of the cation concentration. The concentration of ions can be expressed in terms of pOH. Addition of a base to water will reduce the hydrogen cation concentration, POH can be kept at a nearly constant value with various buffer solutions. In aqueous solution the hydroxide ion is a base in the Brønsted–Lowry sense as it can accept a proton from a Brønsted–Lowry acid to form a water molecule and it can also act as a Lewis base by donating a pair of electrons to a Lewis acid. In aqueous solution both hydrogen and hydroxide ions are solvated, with hydrogen bonds between oxygen and hydrogen atoms. Indeed, the bihydroxide ion H 3O−2 has been characterized in the solid state and this compound is centrosymmetric and has a very short hydrogen bond that is similar to the length in the bifluoride ion HF−2. In aqueous solution the hydroxide ion forms strong bonds with water molecules. A consequence of this is that concentrated solutions of sodium hydroxide have high viscosity due to the formation of a network of hydrogen bonds as in hydrogen fluoride solutions. In solution, exposed to air, the ion reacts rapidly with atmospheric carbon dioxide, acting as an acid, to form, initially. OH− + CO2 ⇌ HCO−3 The equilibrium constant for this reaction can be specified either as a reaction with dissolved carbon dioxide or as a reaction with carbon dioxide gas. At neutral or acid pH, the reaction is slow, but is catalyzed by the carbonic anhydrase. Solutions containing the hydroxide ion attack glass, in this case, the silicates in glass are acting as acids
31.
Clay
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Clay is a fine-grained natural rock or soil material that combines one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure. Clays are plastic due to water content and become hard, brittle. Depending on the content in which it is found, clay can appear in various colours from white to dull grey or brown to deep orange-red. Although many naturally occurring deposits include both silts and clay, clays are distinguished from other fine-grained soils by differences in size, silts, which are fine-grained soils that do not include clay minerals, tend to have larger particle sizes than clays. There is, however, some overlap in size and other physical properties. The distinction between silt and clay varies by discipline, geologists and soil scientists usually consider the separation to occur at a particle size of 2 µm, sedimentologists often use 4–5 μm, and colloid chemists use 1 μm. Geotechnical engineers distinguish between silts and clays based on the plasticity properties of the soil, as measured by the soils Atterberg limits, ISO14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. These solvents, usually acidic, migrate through the rock after leaching through upper weathered layers. In addition to the process, some clay minerals are formed through hydrothermal activity. There are two types of deposits, primary and secondary. Primary clays form as residual deposits in soil and remain at the site of formation, secondary clays are clays that have been transported from their original location by water erosion and deposited in a new sedimentary deposit. Clay deposits are associated with very low energy depositional environments such as large lakes. Depending on the source, there are three or four main groups of clays, kaolinite, montmorillonite-smectite, illite, and chlorite. Chlorites are not always considered to be a clay, sometimes being classified as a group within the phyllosilicates. There are approximately 30 different types of clays in these categories. Varve is clay with visible annual layers, which are formed by deposition of those layers and are marked by differences in erosion. This type of deposit is common in glacial lakes
32.
Blowout (geomorphology)
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Blowouts are sandy depressions in a sand dune ecosystem caused by the removal of sediments by wind. Commonly found in settings and arid margins, blowouts tend to form when wind erodes into patches of bare sand on stabilized vegetative dunes. Generally, blowouts don’t form on actively flowing dunes due to the fact that they need to be bound by some extent, the depression may continue until it hits a non-erodible substrate or morphology limits it. Protective Skin In the first case, the objective for the protective skin is to resist disturbances that will form open exposures. To prevent erosion, vegetation helps reduce stress by covering the surface. The protective skin is composed of vegetation that is above and below ground surface, additionally, the protective skin can also be composed of a wide variety of species that could constitute environments like grasslands and forest. Even though a few species can be classed as a colonizer. Mostly due to changes in the climate, colonizer species heavily rely on conditions of the environment, coastal sand dunes are found just inland from a beach, and are formed as the wind blows dry sand inland beyond the beach. It follows that this can happen when there is an area of reasonably flat land inland from the beach. In time, this rather inhospitable surface will be colonised by pioneer species and these species will stabilise the dunes and prevent them moving any more. The process of plant succession will eventually see these dunes converted to woodland, blowouts provide an important habitat for flora and fauna. Disturbances are generally phrases to define a cause that creates an exposure in the vegetative skin, despite the fact that many factors could influence blowout formations, disturbances usually have three characteristics to determine if a depression will form and expand. The first property states that disturbances must have a magnitude greater than the toughness of the protective vegetative skin. Simply if the breach cannot remove the shielding vegetation wind erosion cannot create a depression in stabilized dunes, the second property asserts that sediment transportation in an exposure would be limited if exposure’s spatial coverage is too small. Presuming that the opening is very compacted, the length would also be very cramped which doesn’t allow much sediment particles to be moved out of the exposure. Lastly the third property exclaims that spatial configuration of the disturbed openings greatly influences the fetch length, thus, although the scale of the disturbances does assist in blowout formation, these characteristics generally help dictate if Aeolian processes can create a depression or not. Once an exposure has been spawned, the morphology of the blowout depends on the interaction of wind speed and direction with the stabilized dune’s vegetation and topography. There is a range of blowout types that form depending on these factors, however
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Landform
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A landform is a natural feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography, landforms are categorized by characteristic physical attributes such as elevation, slope, orientation, stratification, rock exposure, and soil type. Oceans and continents exemplify the highest-order landforms, landform elements are parts of a high-order landforms that can be further identified and systematically given a cohesive definition such as hill-tops, shoulders, saddles, foreslopes and backslopes. Some generic landform elements including, pits, peaks, channels, ridges, passes, pools, Terrain is the third or vertical dimension of land surface. Topography is the study of terrain, although the word is used as a synonym for relief itself. When relief is described underwater, the term bathymetry is used, in cartography, many different techniques are used to describe relief, including contour lines and TIN. Elementary landforms are the smallest homogeneous divisions of the land surface and these are areas with relatively homogeneous morphometric properties, bounded by lines of discontinuity. A plateau or a hill can be observed at various scales ranging from few hundred meters to hundreds of kilometers, hence, the spatial distribution of landforms is often scale-dependent as is the case for soils and geological strata. A number of factors, ranging from plate tectonics to erosion and deposition, can generate, landforms do not include man-made features, such as canals, ports and many harbors, and geographic features, such as deserts, forests, and grasslands. Many of the terms are not restricted to refer to features of the planet Earth, examples are mountains, hills, polar caps, and valleys, which are found on all of the terrestrial planets. The scientific study of landforms is known as geomorphology, landforms may be extracted from a digital elevation model using some automated techniques where the data has been gathered by modern satellites and stereoscopic aerial surveillance cameras. Until recently, compiling the data found in data sets required time consuming. The most detailed DEMs available are measured directly using LIDAR techniques, geomorphology Land List of landforms Open-geomorphometry project Terrain Open-Geomorphometry Project
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Depression (geology)
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A depression in geology is a landform sunken or depressed below the surrounding area. Erosion-related, Blowout, a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils, glacial valley, a depression carved by erosion by a glacier. River valley, a depression carved by erosion by a river. Area of subsidence caused by the collapse of a structure such as sinkholes in karst terrain. Sink, an endorheic depression generally containing a persistent or intermittent lake, collapse-related, Sinkhole, a depression formed as a result of the collapse of rocks lying above a hollow. This is common in karst regions, kettle, a shallow, sediment-filled body of water formed by melting glacial remnants in terminal moraines. Thermokarst hollow, caused by loss of the ground as the result of permafrost thawing. Impact-related, Impact crater, a depression created by an impact such as a meteorite crater, sedimentary-related, Sedimentary basin, in sedimentology, an area thickly filled with sediment in which the weight of the sediment further depresses the floor of the basin. Structural or tectonic-related, Structural basin, a depression, a region of tectonic downwarping as a result of isostasy or subduction. Graben or rift valley, fallen and typically linear depressions or basins created by rifting in a region under tensional tectonic forces, pull-apart basin caused by offset in a strike slip or transform fault. Oceanic trench, a linear depression on the ocean floor. Oceanic trenches are caused by subduction of oceanic crust beneath either oceanic crust or continental crust, pit crater, a volcanic depression smaller than a caldera formed by a sinking, or caving in, of the ground surface lying over a void. Maar, a resulting from phreatomagmatic eruption or diatreme explosion. Cryptodepression List of places on land with elevations below sea level
35.
Yardang
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Yardangs become elongated features typically three or more times longer than wide, and when viewed from above, resemble the hull of a boat. Facing the wind is a steep, blunt face that gradually lower and narrower toward the lee end. Yardangs are formed by erosion, typically of an originally flat surface formed from areas of harder and softer material. The soft material is eroded and removed by the wind, the resulting pattern of yardangs is therefore a combination of the original rock distribution, and the fluid mechanics of the air flow and resulting pattern of erosion. The word itself is of Turkic origin, meaning ‘steep bank’, a yardang is formed in cohesive material. Hedin first found the wind-sculptured clay terraces or yardangs in the dried up riverbed of the Kurruk-daria in Central Asia, however, yardangs can be found in most deserts across the globe. Yardangs come in a range of sizes, and are divided into three different categories, mega-yardangs, meso-yardangs, and micro-yardangs. A large concentration of mega-yardangs are found near the Tibesti Mountains in the central Sahara, there is a famous yardang at Hole in the Rock in Papago Park in Phoenix, Arizona, a rock formation with a roughly circular hole in it. Another yardang in Arizona is Window Rock, near the town of Window Rock and it is a 60-meter sandstone hill with a very large circular hole in the middle of it. Some geologists have suggested that the Great Sphinx of Egypt is an augmented yardang, pictures from Mars show that the yardang ridges occur on a massive scale there, some individual ridges are tens of kilometers long with intervening valleys nearly 1 km wide. Yardangs on Mars are typically found in the Amazonis region but the best ones are found in the equatorial region, yardangs on Mars demonstrate that much of the eolian erosion is recent since they are sculpted in young geologic units. Yardangs form in environments where water is scarce and the winds are strong, uni-directional. The wind cuts down low-lying areas into parallel ridges which gradually erode into separate hills that take on the shape of a yardang. This process yields a field of yardangs of roughly the same size, alternatively, one can be formed by the migration of a dune that leaves behind a cemented core. As the process of formation continues, typically a trough will form around the base of the yardang, most yardang fields are in sand-poor areas, but the associated troughs, especially in grooved terrain, may be invaded by sand. Sometimes this sand will accumulate to build shallow moats around the bottom and they are more commonly created from softer rock types like siltstone, sandstone, shale and limestone, but have also been observed in crystalline rocks such as schist and gneiss. Other common names for them include mud-lions, sphinxlike hills, inselbergs, Koukour, kalut and cretes et couloirs
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Great Sphinx of Giza
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Facing directly from West to East, it stands on the Giza Plateau on the west bank of the Nile in Giza, Egypt. The face of the Sphinx is generally believed to represent the Pharaoh Khafre, cut from the bedrock, the original shape of the Sphinx has been restored with layers of blocks. It measures 238 feet long from paw to tail,66.3 ft high from the base to the top of the head and 62.6 feet wide at its rear haunches. It is the oldest known sculpture in Egypt and is commonly believed to have been built by ancient Egyptians of the Old Kingdom during the reign of the Pharaoh Khafre. The Sphinx is a monolith carved into the bedrock of the plateau, the nummulitic limestone of the area consists of layers which offer differing resistance to erosion, leading to the uneven degradation apparent in the Sphinxs body. The lowest part of the body, including the legs, is solid rock, the body of the lion up to its neck is fashioned from softer layers that have suffered considerable disintegration. The layer in which the head was sculpted is much harder, the Great Sphinx is one of the worlds largest and oldest statues, but basic facts about it are still subject to debate, such as when it was built, by whom and for what purpose. These questions have resulted in the idea of the Riddle of the Sphinx. In the New Kingdom, the Sphinx was called Hor-em-akhet, the English word sphinx comes from the ancient Greek Σφίγξ apparently from the verb σφίγγω, after the Greek sphinx who strangled anyone who failed to answer her riddle. The name may alternatively be a corruption of the phonetically different ancient Egyptian word Ssp-anx. This name is given to royal statues of the Fourth dynasty of ancient Egypt, medieval Arab writers, including al-Maqrīzī, call the Sphinx balhib and bilhaw, which suggest a Coptic influence. The modern Egyptian Arabic name is أبو الهول, the circumstantial evidence mentioned by Hassan includes the Sphinxs location in the context of the funerary complex surrounding the Second Pyramid, which is traditionally connected with Khafra. A diorite statue of Khafre, which was discovered buried upside down along with other debris in the Valley Temple, is claimed as support for the Khafra theory, the Dream Stele, erected much later by the pharaoh Thutmose IV, associates the Sphinx with Khafra. When the stele was discovered, its lines of text were already damaged and incomplete, an extract was translated, which we bring for him, oxen. and all the young vegetables, and we shall give praise to Wenofer. Khaf. the statue made for Atum-Hor-em-Akhet, the Egyptologist Thomas Young, finding the Khaf hieroglyphs in a damaged cartouche used to surround a royal name, inserted the glyph ra to complete Khafras name. When the Stele was re-excavated in 1925, the lines of text referring to Khaf flaked off and were destroyed. In 1857, Auguste Mariette, founder of the Egyptian Museum in Cairo, unearthed the much later Inventory Stela, such an act became common when religious institutions such as temples, shrines and priests domains were fighting for political attention and for financial and economic donations. Gaston Maspero, the French Egyptologist and second director of the Egyptian Museum in Cairo and he supports this by suggesting that Khafras Causeway was built to conform to a pre-existing structure, which, he concludes, given its location, could only have been the Sphinx
37.
Sahara
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The Sahara is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic. Its area of 9,200,000 square kilometres is comparable to the area of the United States. The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan. It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains. To the south, it is bounded by the Sahel, a belt of tropical savanna around the Niger River valley. The Sahara can be divided into several regions including, the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténéré desert, the name Sahara is derived from ṣaḥārā, the plural of the Arabic word for desert. The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and it covers 9 million square kilometres, amounting to 31% of Africa. If all areas with an annual precipitation of less than 250 mm were included. It is one of three physiographic provinces of the African massive physiographic division. The Sahara is mainly rocky hamada, Ergs form only a minor part, wind or rare rainfall shape the desert features, sand dunes, dune fields, sand seas, stone plateaus, gravel plains, dry valleys, dry lakes, and salt flats. Unusual landforms include the Richat Structure in Mauritania, several deeply dissected mountains, many volcanic, rise from the desert, including the Aïr Mountains, Ahaggar Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas, and the Red Sea hills. The highest peak in the Sahara is Emi Koussi, a volcano in the Tibesti range of northern Chad. The central Sahara is hyperarid, with sparse vegetation, the northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and desert shrub, with trees and taller shrubs in wadis, where moisture collects. In the central, hyperarid region, there are subdivisions of the great desert, Tanezrouft, the Ténéré, the Libyan Desert, the Eastern Desert. These extremely arid areas often receive no rain for years, the northern limit also corresponds to the 100 mm isohyet of annual precipitation. To the south, the Sahara is bounded by the Sahel, the southern limit of the Sahara is indicated botanically by the southern limit of Cornulaca monacantha, or northern limit of Cenchrus biflorus, a grass typical of the Sahel. According to climatic criteria, the limit of the Sahara corresponds to the 150 mm isohyet of annual precipitation. The Sahara is the worlds largest low-latitude hot desert and this steady descending airflow causes a warming and a drying effect in the upper troposphere
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Sahel
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The Sahel is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea, the Arabic word sāḥil literally means shore, coast, while the word Sahara is derived from the Arabic word for desert. Together, these names evoke an image of the Sahels vegetation as a coastline on the Saharas ocean of sand, historically, the western part of the Sahel was sometimes known as the Sudan region. This belt was roughly located between the Sahara and the areas of West Africa. It is an ecoregion of semi-arid grasslands, savannas, steppes. The topography of the Sahel is mainly flat, most of the region lies between 200 and 400 meters in elevation, several isolated plateaus and mountain ranges rise from the Sahel, but are designated as separate ecoregions because their flora and fauna are distinct from the surrounding lowlands. Annual rainfall varies from around 100–200 mm in the north of the Sahel to around 600 mm in the south, the Sahel is mostly covered in grassland and savanna, with areas of woodland and shrubland. Grass cover is continuous across the region, dominated by annual grass species such as Cenchrus biflorus, Schoenefeldia gracilis. Species of acacia are the dominant trees, with Acacia tortilis the most common, along with Acacia senegal, other tree species include Commiphora africana, Balanites aegyptiaca, Faidherbia albida, and Boscia senegalensis. In the northern part of the Sahel, areas of shrub, including Panicum turgidum and Aristida sieberana, alternate with areas of grassland. During the long dry season, many lose their leaves. The larger species have greatly reduced in number by over-hunting and competition with livestock. The seasonal wetlands of the Sahel are important for birds moving within Africa. The Sahel has a tropical, hot steppe climate, the climate is typically hot, sunny, dry and somewhat windy all year long. The Sahels climate is similar to, but less extreme than, the Sahel mainly receives a low to a very low amount of precipitation annually. The steppe has a long, prevailing dry season and a short rainy season. The precipitation is extremely irregular, and varies considerably from season to season. Most of the rain falls during only one or two months, while the other months may remain absolutely dry
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Amazon basin
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The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 7,500,000 km2 and it is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname and Venezuela. Most of the basin is covered by the Amazon Rainforest, also known as Amazonia, with a 5,500,000 km2 area of dense tropical forest, this is the largest rainforest in the world. The Amazon River rises in the Andes Mountains at the west of the basin with its tributary the Marañón River in Peru. It is usually considered to be the second longest river in the world, however, a team of Brazilian scientists has claimed that the Amazon is the longest river in the world. It covers about 6,400 km before draining into the Atlantic Ocean, the Amazon and its tributaries form the largest volume of water. The Amazon accounts for about 20% of the water carried to the oceans by rivers. Some of the Amazon rainforests are deforested because of the increasing of cattle ranches, the highest point in the watershed of the Amazon is the peak of Yerupajá at 6,635 m. The Amazon basin formerly flowed west to Pacific Ocean until the Andes formed, politically the basin is divided into the Brazilian Amazônia Legal, the Peruvian Amazon, the Amazon region of Colombia and parts of Bolivia, Ecuador and the Venezuelan state of Amazonas. Plant growth is dense and its variety of inhabitants is comparatively high due to the heavy rainfall. Little sunlight reaches the ground due to the roof canopy by plants. The ground remains dark and damp and only shade tolerant vegetation will grow here, orchids and bromeliads exploit trees and other plants to get closer to the sunlight. They grow hanging onto the branches or tree trunks with aerial roots, not as parasites, species of tropical trees native to the Amazon include Brazil nut, rubber tree and Assai palm. More than 1,400 species of mammals are found in the Amazon and its larger mammals include the jaguar, ocelot, capybara and South American tapir. About 1500 bird species inhabit the Amazon Basin, the biodiversity of the Amazon and the sheer number of diverse bird species is given by the number of different bird families that reside in these humid forests. An example of such would be the family, to which the Guianan cock-of-the-rock belong. Birds such as toucans, and hummingbirds are found here. Macaws are famous for gathering by the hundreds along the cliffs of the Amazon River
40.
NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration efforts have led by NASA, including the Apollo Moon landing missions, the Skylab space station. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the agency is also responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA shares data with various national and international such as from the Greenhouse Gases Observing Satellite. Since 2011, NASA has been criticized for low cost efficiency, from 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1. In the early 1950s, there was challenge to launch a satellite for the International Geophysical Year. An effort for this was the American Project Vanguard, after the Soviet launch of the worlds first artificial satellite on October 4,1957, the attention of the United States turned toward its own fledgling space efforts. This led to an agreement that a new federal agency based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency was created in February 1958 to develop technology for military application. On July 29,1958, Eisenhower signed the National Aeronautics and Space Act, a NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA, earlier research efforts within the US Air Force and many of ARPAs early space programs were also transferred to NASA. In December 1958, NASA gained control of the Jet Propulsion Laboratory, NASA has conducted many manned and unmanned spaceflight programs throughout its history. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter, the experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a space capsule program, and in turn by a two-man capsule program. This goal was met in 1969 by the Apollo program, however, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, to date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude,260,000 feet. The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force, the design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems
41.
Harmattan
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The Harmattan is a season in the West African subcontinent, which occurs between the end of November and the middle of March. It is characterized by dry and dusty trade wind, of the same name. The name comes from or is related to Ga haramata and it is cold in most places, but can be hot in some places, according to the circumstances. On its passage over the Sahara, it picks up fine dust, the Harmattan season differs from winter, because it is characterized by cold, dry, dust-laden wind, and also wide fluctuations in the ambient temperatures of the day and night. Temperatures can easily be as low as 9 °C all day, the air is particularly dry and desiccating when the Harmattan blows over the region. The wind can increase fire risk and cause severe crop damage, the interaction of the Harmattan with monsoon winds can cause tornadoes. In some countries in West Africa, the amount of dust in the air can severely limit visibility and block the sun for several days. This effect is known as the Harmattan haze and it costs airlines millions of dollars in cancelled and diverted flights each year. When the haze is weak, the skies are clear, the dry air can break the trunks of trees growing in the region. Humidity drops to as low as 15%, which can result in spontaneous nosebleeds for some people, other health effects on humans may include conditions of the skin, eyes, and respiratory system, including aggravation of asthma
42.
West Africa
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West Africa, also called Western Africa and the West of Africa, is the westernmost subregion of Africa. Early human settlers from northern Holocene societies arrived in West Africa around 12,000 B. C, sedentary farming began in, or around the fifth millennium B. C, as well as the domestication of cattle. By 1500 B. C, ironworking technology allowed an expansion of productivity. Northern tribes developed walled settlements and non-walled settlements that numbered at 400, in the forest region, Iron Age cultures began to flourish, and an inter-region trade began to appear. The desertification of the Sahara and the change of the coast cause trade with upper Mediterranean peoples to be seen. Local leather, cloth, and gold also contributed to the abundance of prosperity for many of the following empires. Also, based on the archaeology of city of Kumbi Saleh in modern-day Mauritania, three great kingdoms were identified in Bilad al-Sudan by the ninth century. They included Ghana, Gao and Kanem, the Sosso Empire sought to fill the void, but was defeated by the Mandinka forces of Sundiata Keita, founder of the new Mali Empire. In the 15th century, the Songhai would form a new dominant state based on Gao, in the Songhai Empire, under the leadership of Sonni Ali, further east, Oyo arose as the dominant Yoruba state and the Aro Confederacy as a dominant Igbo state in modern-day Nigeria. The Kingdom of Nri was a West African medieval state in the present-day southeastern Nigeria, the Kingdom of Nri was unusual in the history of world government in that its leader exercised no military power over his subjects. The kingdom existed as a sphere of religious and political influence over a third of Igboland, the Eze Nri managed trade and diplomacy on behalf of the Nri people, and possessed divine authority in religious matters. The Oyo Empire was a Yoruba empire of what is today Western, established in the 15th century, the Oyo Empire grew to become one of the largest West African states. It rose through the organizational skills of the Yoruba, wealth gained from trade. The Benin Empire was an empire located in what is now southern Nigeria. Its capital was Edo, now known as Benin City, Edo and it should not be confused with the modern-day country called Benin, formerly called Dahomey. The Benin Empire was one of the oldest and most highly developed states in the hinterland of West Africa. Olfert Dapper, a Dutch writer, describing Benin in his book Description of Africa and its craft was the most adored and treasured bronze casting in the history of Africa. It was annexed by the British Empire in 1897 during the invasion, in the early 19th century, a series of Fulani reformist jihads swept across Western Africa
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Gobi Desert
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The Gobi Desert is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia, the Gobi is most notable in history as part of the great Mongol Empire, and as the location of several important cities along the Silk Road. The Gobi is a rain shadow desert, formed by the Himalayan mountain range blocking rain-carrying clouds from the Indian Ocean reaching the Gobi territory, the Gobi measures over 1,600 km from southwest to northeast and 800 km from north to south. The desert is widest in the west, along the joining the Lake Bosten. It occupies an arc of land 1,295,000 km2 in area as of 2007, it is the fifth-largest desert in the world, much of the Gobi is not sandy but has exposed bare rock. The Gobi is a desert, with frost and occasionally snow occurring on its dunes. Besides being quite far north, it is located on a plateau roughly 910–1,520 metres above sea level. An average of approximately 194 millimetres of rain falls annually in the Gobi, additional moisture reaches parts of the Gobi in winter as snow is blown by the wind from the Siberian Steppes. These winds cause the Gobi to reach extremes of temperature ranging from −40 °C or −40 °F in winter to 45 °C or 113 °F in summer, the climate of the Gobi is one of great extremes, combined with rapid changes of temperature of as much as 35 °C. These can occur not only seasonally but within 24 hours, in southern Mongolia, the temperature has been recorded as low as −32.8 °C. In contrast, in Alxa, Inner Mongolia, it rises as high as 37 °C in July, average winter minimums are a frigid −25 °C while summertime temperatures are warm to hot, with highs that range up to 50 °C. Most of the falls during the summer. Hence, the icy sandstorms and snowstorms of spring and early summer plus early January, the Gobi Desert is the source of many important fossil finds, including the first dinosaur eggs. They are occasionally visited by snow leopards, brown bears, drought-adapted shrubs in the desert included gray sparrows saltwort, gray sagebrush, and low grasses such as needle grass and bridlegrass. Several large nature reserves have established in the Gobi, including Gobi Gurvansaikhan National Park, Great Gobi A. The area is vulnerable to trampling by livestock and off-road vehicles, in Mongolia, grasslands have been degraded by goats, which are raised by nomadic herders as source of cashmere wool. The economic trends of livestock privatization and the collapse of the economy have caused people to return to subsistence rural lifestyles. Large copper and gold deposits located at Oyuu Tolgoi, about 80 kilometres from the Chinese border into Mongolia, are being investigated for development as mining operations
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Asian Dust
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Asian Dust is a meteorological phenomenon which affects much of East Asia year round but especially during the spring months. The dust originates in the deserts of Mongolia, northern China and Kazakhstan where high-speed surface winds and intense dust storms kick up dense clouds of fine, dry soil particles. These clouds are then carried eastward by prevailing winds and pass over China, North and South Korea, sometimes, the airborne particulates are carried much further, in significant concentrations which affect air quality as far east as the United States. Griffin, also with the USGS in St. Petersburg, We now find that isnt true, areas affected by the dust experience decreased visibility and the dust is known to cause a variety of health problems, including sore throat and asthma in otherwise healthy people. Often, people are advised to avoid or minimize outdoor activities, for those already with asthma or respiratory infections, it can be fatal. The dust has shown to increase the daily mortality rate in one affected region by 1. 7%. The dust storms also affect wildlife particularly hard, destroying crops, habitat, toxic metals propagate up the food chain, e. g. from fish to higher mammals. Air visibility is reduced, including cancelled flights, ground travel, outdoor activities, Japan has reported washed clothes stained yellow. Korea Times has reported it costing 3 million won,6000 gallons of water, shanghai on April 3,2007 recorded an air quality index of 500. In the US, a 300 is considered Hazardous and anything over 200 is Unhealthy. Desertification has intensified in China, as 1,740,000 km² of land is dry, it disrupts the lives of 400 million people and causes economic losses of 54 billion yuan a year. El Niño plays a role in Asian dust storms, because winter ice can keep dust from sweeping off the land, in recent years, South Korea and China have participated in reforestation efforts in the source region. This has not affected the problem in a significant way, however, in April 2006, South Korean meteorologists reported the worst yellow dust storm in four years. China also has taken steps, with support, to plant trees in desert areas. But the winds are so strong in places that the trees simply topple or get buried in sand. In 2007, South Korea sent several thousand trees to block the migration of the yellow dust. These trees, however, were planted only by highways, because China told South Korea that the former would decide where the trees would be planted, after inhalation, it can cause long term scarring of lung tissue as well as induce cancer and lung disease. Some of the earliest written records of dust storm activity are recorded in the ancient Chinese literature and it is believed that the earliest Chinese dust storm record was found in the Zhu Shu Ji Nian
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Thar Desert
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The Thar Desert, also known as the Great Indian Desert, is a large, arid region in the northwestern part of the Indian subcontinent that forms a natural boundary between India and Pakistan. It is the worlds 17th largest desert, and the worlds 9th largest subtropical desert, about 85% of the Thar Desert is in India, and the remaining part in Pakistan. In India, it covers about 320,000 km2, forming approximately 10% of the geographic area of India. More than 60% of the lies in the state of Rajasthan and extends into Gujarat, Punjab. This desert comprises a very dry part, the Marusthali region in the west, the Thar Desert extends between the Aravalli Hills in the north-east, the Great Rann of Kutch along the coast and the alluvial plains of the Indus River in the west and north-west. Most of the desert is covered by shifting sand dunes that receive sediments from the alluvial plains. The sand is highly due to strong winds occurring before the onset of the monsoon. The Luni River is the only integrated into the desert. Rainfall is limited to 100–500 mm per year, mostly falling from July to September, salt water lakes in the Thar Desert include the Sambhar, Kuchaman, Didwana in Rajasthan and Kharaghoda in Gujarat. These lakes receive rain water during monsoon and evaporate during the dry season, the salt is derived by the weathering of rocks in the region. Lithic tools belonging to the prehistoric Aterian culture of the Maghreb have been discovered in Middle Paleolithic deposits in the Thar Desert, the soil of the Thar Desert remains dry for much of the year and is prone to wind erosion. High velocity winds blow soil from the desert, depositing some on neighboring fertile lands, the 649 km long Indira Gandhi Canal brings fresh water to the Thar Desert. It was conceived to halt spreading of the desert to fertile areas, there are few local tree species suitable for planting in the desert, which are slow growing. Therefore, exotic species were introduced for plantation. Many species of Eucalyptus, Acacia, Cassia and other genera from Israel, Australia, US, Russia, Zimbabwe, Chile, Peru and Sudan have been tried in Thar Desert. Acacia tortilis has proved to be the most promising species for desert afforestation, there are several protected areas in the Thar Desert. In India, the Desert National Park covers 3,162 km2 and represents the Thar Desert ecosystem and its diverse fauna includes the great Indian bustard, blackbuck, chinkara, fox, Bengal fox, wolf, and caracal. Seashells and massive fossilized tree trunks in this record the geological history of the desert
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Indo-Gangetic Plain
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The region is named after the Indus and the Ganges, and encompasses a number of large urban areas. The Indus-Ganga plain is bound on the north by the Himalayas which feed its numerous rivers and are the source of the alluvium deposited across the region by the two river systems. The southern edge of the plain is marked by the Chota Nagpur Plateau, on the west rises the Iranian Plateau. The region is known for the Indus Valley Civilization, which was responsible for the birth of ancient South Asian culture, during the Vedic and Epic eras of Indian history, this region was referred to as Aryavarta. According to Manusmṛti, Aryavarta is the tract between the Himalaya and the Vindhya ranges, from the Eastern Sea to the Western Sea. During the Islamic period, the Turkish, Afghan and Iranian rulers referred to this region as Hindustan, some geographers subdivide the Indo-Gangetic Plain into several parts, the Sindh, Punjab, Doab, and Bengal regions. This divide is only 300 metres above sea level, causing the perception that the Indus-Ganga Plain appears to be continuous between the two drainage basins, the middle Ganga plain extends from the Yamuna River in the west to the state of West Bengal in the east. The lower Ganges plain and the Assam Valley are more verdant than the middle Ganga plain, the lower Ganga is centered in West Bengal, from which it flows into Bangladesh. After joining the Jamuna, a distributary of Brahmaputra, both form the Ganges Delta. The Brahmaputra rises in Tibet as the Yarlung Zangbo River and flows through Arunachal Pradesh and Assam, as a large plain, the exact extent can vary from source to source. The fertile Terai region is the Nepalese extension of the Plain, the rivers encompassed are the Beas, the Chambal, the Chenab, the Ganga, the Gomti, the Indus, the Ravi, the Sutlej and the Yamuna. The soil is rich in silt, making the one of the most intensely farmed areas of the world. Even rural areas here are densely populated, the Indus-Ganga plains, also known as the Great Plains, are large floodplains of the Indus and the Ganga–Brahmaputra river systems. They run parallel to the Himalaya mountains, from Jammu and Kashmir in the west to Assam in the east, the plains encompass an area of 700,000 km² and vary in width through their length by several hundred kilometres. The major rivers of this system are the Ganga and the Indus along with their tributaries, Beas, Yamuna, Gomti, Ravi, Chambal, Sutlej, extent of the Indo-Gangetic plain across South Asia. As the porosity of this belt is very high, the streams flow underground, the bhabar is generally narrow about 7–15 km wide. The Terai belt — lies next to the Bhabar region and is composed of newer alluvium, the underground streams reappear in this region. The region is excessively moist and thickly forested and it also receives heavy rainfall throughout the year and is populated with a variety of wildlife
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Shamal (wind)
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A shamal is a northwesterly wind blowing over Iraq and the Persian Gulf states, often strong during the day, but decreasing at night. This weather effect occurs anywhere from once to several times a year, mostly in summer, the resulting wind typically creates large sandstorms that impact Iraq, most sand having been picked up from Jordan and Syria. Shamals result from strong northwest winds that are funneled into the Persian Gulf by the mountains of Turkey and Iraq to the northeast and the high plains of Saudi Arabia to the southwest. The winds most commonly are strongest in the Spring to Summer and hence the Shamal events are as well, during that time of year the polar jet stream to the north moves southward to become close to the subtropical jet to the south. The proximity of the two jet streams promotes the formation of strong but often dry cold fronts which create the Shamal, the strong winds of the Shamal form in front of and behind the front. Iraq typically experiences strong wind-driven dust 20 to 50 days per year, according to folklore, the first major shamal occurring around May 25 is known as the Al-Haffar, or driller, since it drills huge depressions in desert sand dunes. The second, arriving in early June, coincides with the star, Thorayya. During this event, which is more violent than the others, near the end of June, the last shamal arrives, known as the Al-Dabaran, or the follower. It is violent and continues for several days, local residents keep doors and windows firmly shut as this shamal includes an all-penetrating fine dust which gets into everything. When a passing storm with a cold front passes over the mountains of Turkey. Temperatures at lower elevations still hover above 105 °Fahrenheit during these events, in Iran, where winter storms can bring heavy snow to the terrain, a layer of dust can settle onto the snowpack. This leads to strong northerly wind over the Persian Gulf for periods up to five days and they are associated with cold temperatures. The places around the Middle East most likely to see the winter variety lie near Lavan Island, Halul Island and they persist from 24 to 36 hours during the winter and occur as frequently as two to three times per month between December and February. A persistent three- to five-day event occurs once or twice a winter. Shamals normally last three to five days, the storm also overwhelmed Baghdads Yarmuk Hospital, which treated more than a thousand people with respiratory distress. From February 1 through February 4,2008, there was a massive dust storm associated with a Shamal wind advected over the Arabian Sea. It was estimated that the edge of the dust storm moved at around 20 km/h. Dust from this storm received press from the media as it swept across the Dubai Desert Classic golf tournament
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