1.
Artificial waterfall
–
An artificial waterfall is a water feature or fountain which imitates a natural waterfall. Artificial waterfalls have long featured in traditional Japanese gardens, where they can serve to highlight a scene or to provide focus. The classic gardening manual Sakuteiki, written in the mid-to-late 11th century, the Cascata delle Marmore is an example of a man-made waterfall created by the ancient Romans. Artificial waterfalls were popular in Europe in the late 19th and early 20th centuries, an early American example is Huntington Waterfalls in Golden Gate Park, San Francisco, California. In 1896, Gardening Magazine reported that it was the artificial waterfall in a public park in North America. Artificial waterfalls installed inside of buildings can be small or quite large, some of the benefits of indoor waterfalls are considered to be their production of white noise, humidity, as well as naturally peaceful feelings engendered among onlookers. Jurong Falls is 30 metres tall, and is located within the open-access Waterfall Aviary at the Jurong Bird Park in Singapore
Artificial waterfall
–
Artificial waterfall in the park of
Bagatelle, France.
Artificial waterfall
–
An indoor waterfall at the International Center, in
Detroit.
Artificial waterfall
–
Chater Garden in Hong Kong
Artificial waterfall
–
Artificial waterfall and sculpture at a transportation company in
Salzburg
2.
Angel Falls
–
Angel Falls is a waterfall in Venezuela. It is the worlds highest uninterrupted waterfall, with a height of 979 meters, the waterfall drops over the edge of the Auyantepui mountain in the Canaima National Park, a UNESCO World Heritage site in the Gran Sabana region of Bolívar State. The falls are along a fork of the Rio Kerepacupai Meru which flows into the Churun River, a tributary of the Carrao River, itself a tributary of the Orinoco River. The waterfall has been known as the Angel Falls since the Mid-20th century, they are named after Jimmie Angel, a US aviator, Angels ashes were scattered over the falls on 2 July 1960. The common Spanish name Salto Ángel derives from his surname, explaining the name change, Chávez was reported to have said, This is ours, long before Angel ever arrived there. However, he said that he would not decree the change of name. Some historians state that the first European to visit the waterfall was Fernando de Berrío, other sources state that the first westerner to see the waterfall was the Catalan explorer Fèlix Cardona in 1927. According to accounts of Venezuelan explorer Ernesto Sánchez La Cruz, he spotted the falls in 1912, Cruz possibly saw the Montoya Falls in the Sierra Pacaraima region, which are more than 500 metres tall. Returning on 9 October 1937, Angel tried to land his Flamingo monoplane El Río Caroní atop Auyan-tepui, Angel and his three companions, including his wife Marie, were forced to descend the tepui on foot. It took them 11 days to make their way back to civilization by the sloping back side, but news of their adventure spread. The name of the waterfall—Salto Angel—was first published on a Venezuelan government map in December 1939, Angels plane remained on top of the tepui for 33 years before being lifted out by helicopter. It was restored at the Aviation Museum in Maracay and now sits outdoors on the front of the airport at Ciudad Bolívar. The first recorded person of European descent to reach the base of the falls was Latvian explorer Aleksandrs Laime and he reached the falls alone in 1946. He was the first to reach the side of falls in the late 1950s. He also reached Angels plane 18 years after the crash landing, on 18 November 1955, Latvian independence day, he announced to Venezuelan newspaper El Nacional that this stream without any known local name should be called after a Latvian river, Gauja. The same year, this name was registered in the National Cartographic Institution of Venezuela, there are no convincing proofs that indigenous Pemon people had named the local streams, as Auyán-tepui was considered to be a dangerous place and was not visited by the indigenous people. However, lately the Pemon name Kerep is used as well, Laime was also the first to clear a trail that leads from the Churun River to the base of the falls. On the way is a viewpoint commonly used to capture the falls in photographs and it is named Mirador Laime in his honor
Angel Falls
–
Angel Falls, Bolívar State, Venezuela
Angel Falls
–
Partly clouded view of Auyán-tepui and Angel Falls (centre) from Isla Raton camp, taken during the end of the dry season
Angel Falls
–
Jimmie Angel's aircraft, El Rio Caroní, exhibited in front of
Ciudad Bolívar airport
3.
Venezuela
–
Venezuela, officially the Bolivarian Republic of Venezuela, is a federal republic located on the northern coast of South America. It is bordered by Colombia on the west, Brazil on the south, Guyana on the east, Venezuela covers 916,445 km2 and has an estimated population of 31775371. The territory now known as Venezuela was colonized by Spain in 1522 amid resistance from indigenous peoples and it gained full independence as a separate country in 1830. During the 19th century, Venezuela suffered political turmoil and autocracy, since 1958, the country has had a series of democratic governments. This new constitution changed the name of the country to República Bolivariana de Venezuela. Venezuela is a presidential republic consisting of 23 states, the Capital District. Venezuela also claims all Guyanese territory west of the Essequibo River, oil was discovered in the early 20th century, and Venezuela has the worlds largest known oil reserves and has been one of the worlds leading exporters of oil. Previously an underdeveloped exporter of commodities such as coffee and cocoa, oil quickly came to dominate exports. The recovery of oil prices in the early 2000s gave Venezuela oil funds not seen since the 1980s, the Venezuelan government then established populist policies that initially boosted the Venezuelan economy and increased social spending, significantly reducing economic inequality and poverty. However, such policies later became controversial since they destabilized the economy, resulting in hyperinflation, an economic depression. According to the most popular and accepted version, in 1499, the stilt houses in the area of Lake Maracaibo reminded the navigator, Amerigo Vespucci, of the city of Venice, so he named the region Veneziola Piccola Venezia. The name acquired its current spelling as a result of Spanish influence, where the suffix -uela is used as a term, thus. The German language 16th century-term for the area, Klein-Venedig, also means little Venice, however, Martín Fernández de Enciso, a member of the Vespucci and Ojeda crew, gave a different account. In his work Summa de geografía, he states that they found people who called themselves the Veneciuela. Thus, the name Venezuela may have evolved from the native word and it is not known how many people lived in Venezuela before the Spanish conquest, it has been estimated at around one million. In addition to indigenous peoples known today, the population included historic groups such as the Kalina, Auaké, Caquetio, Mariche, the Timoto-Cuica culture was the most complex society in Pre-Columbian Venezuela, with pre-planned permanent villages, surrounded by irrigated, terraced fields. They also stored water in tanks and their houses were made primarily of stone and wood with thatched roofs. They were peaceful, for the most part, and depended on growing crops, regional crops included potatoes and ullucos
Venezuela
–
The signing of Venezuela's independence, by
Martín Tovar y Tovar
Venezuela
–
Flag
Venezuela
–
The
Battle of Carabobo, during the
Venezuelan War of Independence
Venezuela
–
José Gregorio Monagas abolished slavery in 1854.
4.
Stream
–
A stream is a body of water with a current, confined within a bed and banks. Streams are important as conduits in the cycle, instruments in groundwater recharge. The biological habitat in the vicinity of a stream is called a riparian zone. Given the status of the ongoing Holocene extinction, streams play an important corridor role in connecting fragmented habitats, the study of streams and waterways in general is known as surface hydrology and is a core element of environmental geography. Brook A stream smaller than a creek, especially one that is fed by a spring or seep and it is usually small and easily forded. A brook is characterised by its shallowness and its bed being composed primarily of rocks, creek In North America, Australia and New Zealand, a small to medium-sized natural stream. Sometimes navigable by motor craft and may be intermittent, in parts of Maryland, New England, the UK and India, a tidal inlet, typically in a salt marsh or mangrove swamp, or between enclosed and drained former salt marshes or swamps. In these cases, the stream is the stream, the course of the seawater through the creek channel at low. River A large natural stream, which may be a waterway, runnel the linear channel between the parallel ridges or bars on a shoreline beach or river floodplain, or between a bar and the shore. Tributary A contributory stream, or a stream which does not reach the sea, sometimes also called a branch or fork. There are a number of names for a stream. Allt is used in Highland Scotland, beck is used in Yorkshire, Lancashire, Dumfriesshire, Cumbria, Norfolk, and Lincolnshire. Bourne or winterbourne is used in the chalk downland of southern England, brook is used in the Midlands, Lancashire and Cheshire. Burn is used in Scotland and North East England, gill or ghyll is seen in the north of England and other areas influenced by Old Norse. Rivulet is an term encountered in Victorian era publications, stream is used in Southern England. Syke is used in lowland Scotland and Cumbria for a seasonal stream, branch is used to name streams in Maryland and Virginia. Falls is also used to name streams in Maryland, for streams/rivers which have waterfalls on them, little Gunpowder Falls and The Jones Falls are actually rivers named in this manner, unique to Maryland. Kill in New York, Pennsylvania, Delaware, and New Jersey comes from a Dutch language word meaning riverbed or water channel, run in Ohio, Maryland, Michigan, New Jersey, Pennsylvania, Virginia, or West Virginia can be the name of a stream
Stream
–
Rocky stream in Italy
Stream
–
Stream in
Arkhangelsk Oblast, Russia
Stream
–
A rocky creek in
Spearfish Canyon,
South Dakota, US
Stream
–
Creek in
Heathcote National Park, Australia
5.
River
–
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water, small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the term river as applied to geographic features. Many names for small rivers are specific to geographic location, examples are run in parts of the United States, burn in Scotland and northeast England. Sometimes a river is defined as being larger than a creek, but not always, Rivers are part of the hydrological cycle. Potamology is the study of rivers while limnology is the study of inland waters in general. Extraterrestrial rivers of liquid hydrocarbons have recently found on Titan. Channels may indicate past rivers on other planets, specifically outflow channels on Mars and rivers are theorised to exist on planets, a river begins at a source, follows a path called a course, and ends at a mouth or mouths. The water in a river is confined to a channel. In larger rivers there is also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be wide in relation to the size of the river channel. This distinction between river channel and floodplain can be blurred, especially in areas where the floodplain of a river channel can become greatly developed by housing. Rivers can flow down mountains, through valleys or along plains, the term upriver refers to the direction towards the source of the river, i. e. against the direction of flow. Likewise, the term describes the direction towards the mouth of the river. The term left bank refers to the bank in the direction of flow. The river channel typically contains a stream of water, but some rivers flow as several interconnecting streams of water. Extensive braided rivers are now found in only a few regions worldwide and they also occur on peneplains and some of the larger river deltas. Anastamosing rivers are similar to braided rivers and are quite rare
River
–
Melting toe of Athabasca Glacier,
Jasper National Park,
Alberta, Canada
River
–
The River Cam from the Green Dragon Bridge, Cambridge (United Kingdom)
River
–
Nile River delta, as seen from Earth orbit. The Nile is an example of a wave-dominated delta that has the classic Greek letter delta (Δ) shape after which river deltas were named.
River
–
A radar image of a 400-kilometre (250 mi) river of methane and ethane near the north pole of Saturn's moon
Titan
6.
Meltwater
–
Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found in the zone of glaciers, where the rate of snow cover is reducing. Meltwater can be produced during volcanic eruptions, in a way in which the more dangerous lahars form. When meltwater pools on the rather than flowing, it forms melt ponds. As the weather gets colder meltwater will often re-freeze, Meltwater can collect or melt under the ices surface. These pools of water, known as subglacial lakes can form due to geothermal heat, Meltwater provides drinking water for a large proportion of the worlds population, as well as providing water for irrigation and hydroelectric plants. Some cities around the world have large lakes that collect snow melt to supplement water supply, cities that source water from meltwater include Melbourne, Canberra, Los Angeles, Las Vegas amongst others. Glacial meltwater comes from glaciers that have receded over time, often, there will be rivers flowing through glaciers into lakes. These brilliantly blue lakes get their color from rock flour, sediment that has been transported through the rivers to the lakes and this sediment comes from rocks grinding together underneath the glacier. The fine powder is suspended in the water and absorbs and scatters varying colors of sunlight. Meltwater also acts as a lubricant in the sliding of glaciers. Using GPS measurements to study ice flow has revealed that movement is greatest in summer when the meltwater levels are highest. Meltwater can be an indication of abrupt climate change and it can also destabilize glacial lakes leading to sudden floods, and destabilize snowpack causing avalanches. Dammed glacial meltwater from a lake that is released suddenly can result in the floods. Historically Meltwater pulse 1A was a prominent feature of the last deglaciation, extreme Ice Survey Groundwater Moulin Snowmelt Surface water June 4,2007, BBC, UN warning over global ice loss United Nations Environment Program, Global Outlook for Ice and Snow
Meltwater
–
Meltwater from
Mount Edith Cavell Cavell Glacier
Meltwater
–
Meltwater in early spring in
a stream in Pennsylvania
Meltwater
–
Refrozen glacial meltwater from the
Canada Glacier, in Antarctica
Meltwater
–
Meltwater in Skaftafellsjökull, Iceland
7.
Iceberg
–
An iceberg or ice mountain is a large piece of freshwater ice that has broken off a glacier or an ice shelf and is floating freely in open water. It may subsequently become frozen into pack ice, as it drifts into shallower waters, it may come into contact with the seabed, a process referred to as seabed gouging by ice. Almost 91% of an iceberg is below the surface of the water, the word iceberg is a partial loan translation from Dutch ijsberg, literally meaning ice mountain, cognate to Danish isbjerg, German Eisberg, Low Saxon Iesbarg and Swedish isberg. Because the density of ice is about 920 kg/m³. The shape of the underwater portion can be difficult to judge by looking at the portion above the surface and this has led to the expression tip of the iceberg, for a problem or difficulty that is only a small manifestation of a larger problem. Icebergs generally range from 1 to 75 metres above sea level, the largest known iceberg in the North Atlantic was 168 metres above sea level, reported by the USCG icebreaker East Wind in 1958, making it the height of a 55-story building. These icebergs originate from the glaciers of western Greenland and may have a temperature of −15 to −20 °C. Icebergs are usually confined by winds and currents to move close to the coast, the largest icebergs recorded have been calved, or broken off, from the Ross Ice Shelf of Antarctica. Iceberg B-15, photographed by satellite in 2000, measured 295 by 37 kilometres and this iceberg was larger than Belgium. When a piece of ice melts, it makes a fizzing sound called Bergie Seltzer. This sound is made when the water-ice interface reaches compressed air trapped in the ice. As this happens, each bubble bursts, making a popping sound, the bubbles contain air trapped in snow layers very early in the history of the ice, that eventually got buried to a given depth and pressurized as it transformed into firn then to glacial ice. About a month later, this split into two pieces upon crashing into Joe Island in the Nares Strait next to Greenland. In June 2011, large fragments of the Petermann Ice Islands were observed off the Labrador coast, iceberg B-17B140 km2,1999, shipping alert issued December 2009. In addition to classification, icebergs can be classified on the basis of their shape. The two basic types of forms are tabular and non-tabular. Tabular icebergs have steep sides and a top, much like a plateau. This type of iceberg, also known as an ice island, can be quite large, Antarctic icebergs formed by breaking off from an ice shelf, such as the Ross Ice Shelf or Filchner-Ronne Ice Shelf, are typically tabular
Iceberg
–
An artist's impression of an iceberg viewed from the side, with the majority underwater
Iceberg
–
Grotto in an iceberg, photographed during the
British Antarctic Expedition of 1911–1913, 5 Jan 1911. Photographer: Herbert Ponting, Alexander Turnbull Library
Iceberg
–
The
calving of Iceberg A-38 off
Ronne Ice Shelf
Iceberg
–
Iceberg A22A in the South
Atlantic Ocean
8.
Ice shelf
–
An ice shelf is a thick floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Canada, the boundary between the floating ice shelf and the grounded ice that feeds it is called the grounding line. The thickness of ice shelves ranges from about 100 to 1000 meters, in contrast, sea ice is formed on water, is much thinner, and forms throughout the Arctic Ocean. It also is found in the Southern Ocean around the continent of Antarctica, Ice shelves are principally driven by gravity-driven pressure from the grounded ice. That flow continually moves ice from the line to the seaward front of the shelf. The primary mechanism of mass loss from ice shelves was thought to have been iceberg calving, typically, a shelf front will extend forward for years or decades between major calving events. Snow accumulation on the surface and melting from the lower surface are also important to the mass balance of an ice shelf. Ice may also accrete onto the underside of the shelf, the density contrast between glacial ice, which is denser than normal ice, and liquid water means that only about 1/9 of the floating ice is above the ocean surface. The worlds largest ice shelves are the Ross Ice Shelf and the Filchner-Ronne Ice Shelf in Antarctica, the term captured ice shelf has been used for the ice over a subglacial lake, such as Lake Vostok. All Canadian ice shelves are attached to Ellesmere Island and lie north of 82°N, Ice shelves that are still in existence are the Alfred Ernest Ice Shelf, Milne Ice Shelf, Ward Hunt Ice Shelf and Smith Ice Shelf. The MClintock Ice Shelf broke up from 1963 to 1966, the Ayles Ice Shelf broke up in 2005, a total of 74 percent of the Antarctic coastline has ice shelves attached. Their aggregate area is over 1,550,000 km2, in the last several decades, glaciologists have observed consistent decreases in ice shelf extent through melt, calving, and complete disintegration of some shelves. The Ellesmere ice shelf reduced by 90 percent in the century, leaving the separate Alfred Ernest, Ayles, Milne, Ward Hunt. A1986 survey of Canadian ice shelves found that 48 km². of ice calved from the Milne, the Ayles Ice Shelf calved entirely on August 13,2005. The Ward Hunt Ice Shelf, the largest remaining section of thick landfast sea ice along the coastline of Ellesmere Island. It further decreased by 27% in thickness between 1967 and 1999, in summer 2002, the Ward Ice Shelf experienced another major breakup. Two sections of Antarcticas Larsen Ice Shelf broke apart into hundreds of small fragments in 1995 and 2002. The breakup events may be linked to the dramatic polar warming trends that are part of global warming, the leading ideas involve enhanced ice fracturing due to surface meltwater and enhanced bottom melting due to warmer ocean water circulating under the floating ice
Ice shelf
–
Close-up of Ross Ice Shelf
Ice shelf
–
Panorama of Ross Ice Shelf
9.
Bedrock
–
BedRock is the second single by hip hop group Young Money Entertainment from their debut collaboration album We Are Young Money. It is performed by Young Money artists Lil Wayne, Gudda Gudda, Nicki Minaj, Drake, Tyga, Jae Millz and it was released as a CD in the United Kingdom on March 22,2010. BedRock is featured as a track on the Japanese and New Zealand editions of Nicki Minajs debut studio album. After being leaked in September 2009 to Lil Wayne fan sites and it was originally titled Girl You Know and the chorus was sung by Omarion and Lil Waynes verse was different, but due to Omarions departure from Young Money, he was replaced by Lloyd. The song was planned to be released as the 3rd official single of the album. Drake interpolates Are You That Somebody by Aaliyah in his verse, Girl, I gotta watch my back, in August 2011, Done Deal Enterprises filed a copyright infringement lawsuit against Lil Wayne, Cash Money, Young Money, and Universal over the song. Blue Marley from Done Deal claims that he wrote BedRock with the same name, bedRocks music video, directed by Dayo and Lil Wayne, was shot on October 21 and released on December 7,2009 and debuted on BETs 106 & Park. The video was featured on MTV Jams that same morning and was posted to MTV. com in January 2010. Cameo appearances are made by ZC, Nixo, Birdman, LoLoFoSho, Lil Chuckee, Beverly, Short Dawg, Winston, Shanell, NBA player J. R. Smith, Mack Maine, and Jay Rock. It features the members of Young Money in a house in Davie and they are later seen outside near the swimming pool of the house. There are five versions of BedRock, the first is titled Girl You Know and Omarion sings the chorus. The second version had Lloyd singing the chorus and Lil Waynes verse was slightly different and this version is the only one to have Lloyd saying Young Lloyd, Young Mula Baby at the end. This version can be found on Gudda Guddas mixtape, Guddaville, in the third version, Lil Waynes verse is slightly different from the first two versions and he says Young Mula Baby in place of Lloyd. This is the version that was released as a single and appears on the album, the last version, titled BedRock Part II is the official remix. Tyga, Nicki Minaj, Gudda Gudda, and Jae Millz verses were all replaced by new verses by Lloyd, Lil Waynes verse on this version is the same one on the second version. In the original video of BedRock when Drake sings I love your sushi roll. A plumper Nicki was sitting against the wall, now in place is another girl with a sushi roll. The fifth version is by Rasheeda, Diamond, Kandi, Lola Monroe, Kandi sings the chorus but instead of saying Mr Flintstone she says Mrs Flintstone BedRock debuted at #36 on the Billboard Hot 100 on the week ending December 12,2009
Bedrock
–
"BedRock"
Bedrock
10.
Whirlpool
–
A whirlpool is a body of swirling water produced by the meeting of opposing currents. The vast majority of whirlpools are not very powerful and very small whirlpools can easily be seen when a bath or a sink is draining, more powerful ones in seas or oceans may be termed maelstroms. Vortex is the term for any whirlpool that has a downdraft. Smaller whirlpools also appear at the base of waterfalls and can also be observed downstream from manmade structures such as weirs. In the case of waterfalls, like Niagara Falls, these whirlpools can be quite strong. Moskstraumen is a system of whirlpools in the open seas in the Lofoten Islands off the Norwegian coast. It is the second strongest whirlpool in the world with flow currents reaching speeds as high as 32 km/h and it finds mention in several books and movies. The maelstrom of Saltstraumen is the Earths strongest maelstrom, and is located close to the Arctic Circle,33 km round the bay on the Highway 17, south-east of the city of Bodø, Norway. The strait at its narrowest is 150 m in width and water funnels through the four times a day. It is estimated that 400 million cubic meters of water passes the narrow strait during this event, the water is creamy in colour and most turbulent during high tide, which is witnessed by thousands of tourists. It reaches speeds of 40 km/h, with speed of about 13 km/h. As navigation is dangerous in this only a small slot of time is available for large ships to pass through. Its impressive strength is caused by the worlds strongest tide occurring in the location during the new. A narrow channel of 3 km length connects the outer Saltfjord with its extension, the Corryvreckan is a narrow strait between the islands of Jura and Scarba, in Argyll and Bute, on the northern side of the Gulf of Corryvreckan, Scotland. It is the third-largest whirlpool in the world, though it was initially classified as non-navigable by the British navy it was later categorized as extremely dangerous. A documentary team from Scottish independent producers Northlight Productions once threw a mannequin into the Corryvreckan with a life jacket, the mannequin was swallowed and spat up far down current with a depth gauge reading of 262 metres with evidence of being dragged along the bottom for a great distance. Old Sow whirlpool is located between Deer Island, New Brunswick, Canada, and Moose Island, Eastport, Maine and it is given the epithet pig-like as it makes a screeching noise when the vortex is at its full fury. The smaller whirlpools around this Old Sow are known as Piglets. the Naruto whirlpools are located in the Naruto Strait near Awaji Island in Japan, which have speeds of 26 km/h
Whirlpool
–
A whirlpool in a glass of water
Whirlpool
–
The
Niagara Whirlpool
Whirlpool
–
A small whirlpool in Tionesta Creek in the
Allegheny National Forest
Whirlpool
–
Whirlpool in a small pond
11.
Stratum
–
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The stratum is the unit in a stratigraphic column and forms the basis of the study of stratigraphy. Each layer is one of a number of parallel layers that lie one upon another. They may extend over hundreds of thousands of kilometers of the Earths surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a mode of deposition, river silt, beach sand, coal swamp, sand dune, lava bed. Geologists study rock strata and categorize them by the material of beds, each distinct layer is typically assigned to the name of sheet, usually based on a town, river, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is an exposure of dark, occasionally fossiliferous. Slight distinctions in material in a formation may be described as members, formations are collected into groups while groups may be collected into supergroups. Archaeological horizon Geologic formation Geologic map Geologic unit Law of superposition Bed GeoWhen Database
Stratum
–
Strata in
Salta (
Argentina).
Stratum
–
Goldenville strata in quarry in
Bedford,
Canada. These are
Middle Cambrian marine sediments. This formation covers over half of
Nova Scotia and is recorded as being 29,000 feet thick in some areas.
Stratum
Stratum
12.
Rock shelter
–
A rock shelter is a shallow cave-like opening at the base of a bluff or cliff. In arid areas, wind erosion can be an important factor in rockhouse formation, erosion from moving water is seldom a significant factor. Many rock shelters are found under waterfalls, Rock shelter formation types Rock shelters are often important archaeologically. Because rock shelters form natural shelters from the weather, prehistoric humans often used them as living-places, and left behind debris, tools, in mountainous areas the shelters can also be important for mountaineers. In western Connecticut and eastern New York, many shelters are known by the colloquialism leatherman caves. Sandstone can be used as shingles for roof tops when possible, the Cumberland stitchwort is an endangered species of plant which is found only in rock shelters in Kentucky and Tennessee. Gatecliff Rockshelter Kinlock Shelter Mesa Verde Overhang Roc-aux-Sorciers Shelter Rock Walnut Canyon
Rock shelter
–
The rock shelter for which
Indian Cave State Park is named.
Rock shelter
–
Rock shelter in the
Little Carpathians
Rock shelter
–
Shepherds' rock shelter in
Lahaul, India
Rock shelter
–
Rock shelter at
Strouds Run State Park
13.
Outcrop
–
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. However, in places where the cover is removed through erosion or tectonic uplift. In Finland, glacial erosion during the last glacial maximum, followed by scouring by sea waves, bedrock and superficial deposits may also be exposed at the Earths surface due to human excavations such as quarrying and building of transport routes. Outcrops allow direct observation and sampling of the bedrock in situ for geologic analysis, in situ measurements are critical for proper analysis of geological history and outcrops are therefore extremely important for understanding the geologic time scale of earth history. Outcrops are also important for understanding fossil assemblages, paleo-environment. An outcrop example in California is the Vasquez Rocks, familiar from location shooting use in many films, list of rock formations Geological formation Geologic time scale Media related to Outcrops at Wikimedia Commons
Outcrop
–
View of a bedrock outcrop near
San Carlos Water,
Falkland Islands
Outcrop
–
Granite outcrops at
Silesian Stones Mountain in southwestern
Poland.
Outcrop
–
Serrote Branco's outcrop.
Caicó,
Brazil.
Outcrop
–
A typical shore outcrop scoured by ancient glaciers in
Espoo,
Finland.
14.
Abrasion (geology)
–
Abrasion is the mechanical scraping of a rock surface by friction between rocks and moving particles during their transport by wind, glacier, waves, gravity, running water or erosion. After friction, the moving particles dislodge loose and weak debris from the side of the rock, the intensity of abrasion depends on the hardness, concentration, velocity and mass of the moving particles. Coastal abrasion occurs as breaking waves which contain sand and larger fragments erode the shoreline or headland and this removes material resulting in undercutting and possible collapse of unsupported overhanging cliffs. Abrasion platforms are shore platforms where wave action abrasion is a prominent process, if it is currently being fashioned, it will be exposed only at low tide, but there is a possibility that the wave-cut platform will be hidden sporadically by a mantle of beach shingle. If the platform is exposed above the high-water mark, it is probably a raised beach platform. Erosion Glacial striation Sedimentary Marine terrace
Abrasion (geology)
–
Glacially abraded
rocks in western
Norway near
Jostedalsbreen glacier.
Abrasion (geology)
–
Polish coast of the
Baltic Sea
15.
Plunge pool
–
A plunge pool is a depression at the base of a waterfall created by the erosional force of falling water and rocks where it lands. The swirling water, sometimes carrying rocks within it, erodes the riverbed into a basin, often featuring irregular, plunge pools can remain after the waterfall has ceased to exist or the stream has been diverted. Plunge pools are erosional features which occur in the stage of a river. When soft rock has been eroded back to a knickpoint, water constantly bombards its base, because this rock is often less dense than surrounding strata, the water from the higher grade continues eroding downward. List of waterfalls by flow rate List of waterfalls by type Riffle Stream gradient Sustainable landscape architecture Tinaja USGS, Stream Modeling website
Plunge pool
–
Seljalandsfoss plunge pool (Iceland)
Plunge pool
–
Ponds
16.
Kinetic energy
–
In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes, the same amount of work is done by the body in decelerating from its current speed to a state of rest. In classical mechanics, the energy of a non-rotating object of mass m traveling at a speed v is 12 m v 2. In relativistic mechanics, this is an approximation only when v is much less than the speed of light. The standard unit of energy is the joule. The adjective kinetic has its roots in the Greek word κίνησις kinesis, the dichotomy between kinetic energy and potential energy can be traced back to Aristotles concepts of actuality and potentiality. The principle in classical mechanics that E ∝ mv2 was first developed by Gottfried Leibniz and Johann Bernoulli, Willem s Gravesande of the Netherlands provided experimental evidence of this relationship. By dropping weights from different heights into a block of clay, Émilie du Châtelet recognized the implications of the experiment and published an explanation. The terms kinetic energy and work in their present scientific meanings date back to the mid-19th century, early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis, who in 1829 published the paper titled Du Calcul de lEffet des Machines outlining the mathematics of kinetic energy. William Thomson, later Lord Kelvin, is given the credit for coining the term kinetic energy c, energy occurs in many forms, including chemical energy, thermal energy, electromagnetic radiation, gravitational energy, electric energy, elastic energy, nuclear energy, and rest energy. These can be categorized in two classes, potential energy and kinetic energy. Kinetic energy is the movement energy of an object, Kinetic energy can be transferred between objects and transformed into other kinds of energy. Kinetic energy may be best understood by examples that demonstrate how it is transformed to, for example, a cyclist uses chemical energy provided by food to accelerate a bicycle to a chosen speed. On a level surface, this speed can be maintained without further work, except to overcome air resistance, the chemical energy has been converted into kinetic energy, the energy of motion, but the process is not completely efficient and produces heat within the cyclist. The kinetic energy in the moving cyclist and the bicycle can be converted to other forms, for example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top. The kinetic energy has now largely converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. Since the bicycle lost some of its energy to friction, it never regains all of its speed without additional pedaling, the energy is not destroyed, it has only been converted to another form by friction
Kinetic energy
–
The cars of a
roller coaster reach their maximum kinetic energy when at the bottom of their path. When they start rising, the kinetic energy begins to be converted to gravitational
potential energy. The sum of kinetic and potential energy in the system remains constant, ignoring losses to
friction.
17.
Earthquakes
–
An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earths lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to people around. The seismicity or seismic activity of an area refers to the frequency, type, Earthquakes are measured using measurements from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe and these two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly imperceptible or weak and magnitude 7 and over potentially cause damage over larger areas. The largest earthquakes in historic times have been of magnitude slightly over 9, intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the damage to structures it causes. At the Earths surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground, when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity, in its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of faults, but also by other events such as volcanic activity, landslides, mine blasts. An earthquakes point of rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter, tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior, once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the portion of the fault. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface and this process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of a total energy is radiated as seismic energy. Most of the energy is used to power the earthquake fracture growth or is converted into heat generated by friction
Earthquakes
–
Global plate tectonic movement
Earthquakes
–
Global earthquake
epicenters, 1963–1998
Earthquakes
–
Aerial photo of the San Andreas Fault in the
Carrizo Plain, northwest of Los Angeles
Earthquakes
–
Collapsed Gran Hotel building in the
San Salvador metropolis, after the shallow
1986 San Salvador earthquake during mid civil war El Salvador.
18.
Landslides
–
A landslide, also known as a landslip, is a form of mass wasting that includes a wide range of ground movements, such as rockfalls, deep failure of slopes, and shallow debris flows. Landslides can occur underwater, called a submarine landslide, coastal, although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability. Typically, pre-conditional factors build up specific sub-surface conditions that make the prone to failure. Landslides occur when the changes from a stable to an unstable condition. A change in the stability of a slope can be caused by a number of factors, slope material that becomes saturated with water may develop into a debris flow or mud flow. The resulting slurry of rock and mud may pick up trees, houses and cars, debris flow is often mistaken for flash flood, but they are entirely different processes. Muddy-debris flows in alpine areas cause severe damage to structures and infrastructure, muddy-debris flows can start as a result of slope-related factors and shallow landslides can dam stream beds, resulting in temporary water blockage. As the impoundments fail, an effect may be created, with a remarkable growth in the volume of the flowing mass. The solid–liquid mixture can reach densities of up to 2,000 kg/m3, for a small basin in the Italian Alps affected by a debris flow, estimated a peak discharge of 750 m3/s for a section located in the middle stretch of the main channel. At the same section, the maximum foreseeable water discharge, was 19 m3/s. Earthflows are downslope, viscous flows of saturated, fine-grained materials, typically, they can move at speeds from 0.17 to 20 km/h. Though these are a lot like mudflows, overall they are slow moving and are covered with solid material carried along by flow from within. They are different from fluid flows which are more rapid, clay, fine sand and silt, and fine-grained, pyroclastic material are all susceptible to earthflows. The velocity of the earthflow is all dependent on how much content is in the flow itself, if there is more water content in the flow. This thereby creates a bulging lobe which advances with a slow, as these lobes spread out, drainage of the mass increases and the margins dry out, thereby lowering the overall velocity of the flow. This process causes the flow to thicken, the bulbous variety of earthflows are not that spectacular, but they are much more common than their rapid counterparts. They develop a sag at their heads and are derived from the slumping at the source. Earthflows occur much more during periods of precipitation, which saturates the ground
Landslides
–
The Mameyes Landslide, in the Mameyes
neighborhood of barrio
Portugués Urbano in Ponce,
Puerto Rico, which buried more than 100 homes, was caused by extensive accumulation of rains and, according to some sources, lightning.
Landslides
–
Computer simulation of a "slump" landslide in
San Mateo County, California (USA) in January 1997
Landslides
–
The landslide at
Surte in Sweden, 1950. It was a
quick clay slide killing one person.
Landslides
–
Amboori debris flow, occurred on 9 November 2001 in Kerala, India. The event killed 39 people.
19.
Volcano
–
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
Volcano
–
Cleveland Volcano in the
Aleutian Islands of
Alaska photographed from the
International Space Station, May 2006
Volcano
–
Ash plumes reached a height of 19 kilometres (12 mi) during the climactic
explosive eruption at
Mount Pinatubo, Philippines in 1991.
Volcano
–
A 2007 eruptive column at
Mount Etna producing volcanic ash, pumice and lava bombs
Volcano
–
Ubinas Volcano
20.
Fault (geology)
–
In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement as a result of rock-mass movement. Large faults within the Earths crust result from the action of tectonic forces. Energy release associated with movement on active faults is the cause of most earthquakes. A fault plane is the plane that represents the surface of a fault. A fault trace or fault line is the intersection of a plane with the ground surface. A fault trace is also the line commonly plotted on maps to represent a fault. Since faults do not usually consist of a single, clean fracture, the two sides of a non-vertical fault are known as the hanging wall and footwall. By definition, the wall occurs above the fault plane. This terminology comes from mining, when working a tabular ore body, because of friction and the rigidity of rocks, they cannot glide or flow past each other easily, and occasionally all movement stops. A fault in ductile rocks can also release instantaneously when the rate is too great. The energy released by instantaneous strain-release causes earthquakes, a common phenomenon along transform boundaries, slip is defined as the relative movement of geological features present on either side of a fault plane, and is a displacement vector. A faults sense of slip is defined as the motion of the rock on each side of the fault with respect to the other side. In practice, it is only possible to find the slip direction of faults. Based on direction of slip, faults can be categorized as, strike-slip. Dip-slip, offset is predominantly vertical and/or perpendicular to the fault trace, oblique-slip, combining significant strike and dip slip. The fault surface is usually vertical and the footwall moves either left or right or laterally with very little vertical motion. Strike-slip faults with left-lateral motion are known as sinistral faults. Those with right-lateral motion are known as dextral faults
Fault (geology)
–
Large normal fault in
Triassic to
Lower Jurassic Blue Anchor Formation sediments near
Blue Anchor,
Somerset, UK, with several smaller normal faults in its hanging wall
Fault (geology)
–
A fault in the Grands Causses as seen from
Bédarieux,
France. The left side moved down relative to the right side
Fault (geology)
–
Microfault showing a
piercing point (the coin's diameter is 18 mm)
Fault (geology)
–
The Piqiang Fault, a northwest trending strike-slip fault in the
Taklamakan Desert south of the
Tien Shan Mountains, China (40.3°N, 77.7°E)
21.
Glacial trough
–
A glacier is a persistent body of dense ice that is constantly moving under its own weight, it forms where the accumulation of snow exceeds its ablation over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs and they also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice, between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earths land surface, continental glaciers cover nearly 13,000,000 km2 or about 98 percent of Antarcticas 13,200,000 km2, with an average thickness of 2,100 m. Greenland and Patagonia also have huge expanses of continental glaciers, Glacial ice is the largest reservoir of fresh water on Earth. Within high altitude and Antarctic environments, the temperature difference is often not sufficient to release meltwater. A large piece of compressed ice, or a glacier, appears blue as large quantities of water appear blue and this is because water molecules absorb other colors more efficiently than blue. The other reason for the color of glaciers is the lack of air bubbles. Air bubbles, which give a color to ice, are squeezed out by pressure increasing the density of the created ice. The word Glaceon is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, the processes and features caused by or related to glaciers are referred to as glacial. The process of establishment, growth and flow is called glaciation. The corresponding area of study is called glaciology, Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, and behavior, cirque glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier, a large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have a less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called ice sheets or continental glaciers, several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces, the only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of water, enough that if both melted, global sea levels would rise by over 70 m
Glacial trough
–
The
Baltoro Glacier in the
Karakoram,
Baltistan, Northern Pakistan. At 62 kilometres (39 mi) in length, it is one of the longest alpine glaciers on earth.
Glacial trough
–
Ice calving from the
terminus of the
Perito Moreno Glacier in western
Patagonia, Argentina
Glacial trough
–
The
Aletsch Glacier, the largest glacier of the
Alps, in Switzerland
Glacial trough
–
The
Quelccaya Ice Cap is the largest glaciated area in the
tropics, in Peru
22.
Glacier
–
A glacier is a persistent body of dense ice that is constantly moving under its own weight, it forms where the accumulation of snow exceeds its ablation over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs and they also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice, between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earths land surface, continental glaciers cover nearly 13,000,000 km2 or about 98 percent of Antarcticas 13,200,000 km2, with an average thickness of 2,100 m. Greenland and Patagonia also have huge expanses of continental glaciers, Glacial ice is the largest reservoir of fresh water on Earth. Within high altitude and Antarctic environments, the temperature difference is often not sufficient to release meltwater. A large piece of compressed ice, or a glacier, appears blue as large quantities of water appear blue and this is because water molecules absorb other colors more efficiently than blue. The other reason for the color of glaciers is the lack of air bubbles. Air bubbles, which give a color to ice, are squeezed out by pressure increasing the density of the created ice. The word Glaceon is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, the processes and features caused by or related to glaciers are referred to as glacial. The process of establishment, growth and flow is called glaciation. The corresponding area of study is called glaciology, Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, and behavior, cirque glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier, a large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have a less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called ice sheets or continental glaciers, several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces, the only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of water, enough that if both melted, global sea levels would rise by over 70 m
Glacier
–
The
Baltoro Glacier in the
Karakoram,
Baltistan, Northern Pakistan. At 62 kilometres (39 mi) in length, it is one of the longest alpine glaciers on earth.
Glacier
–
Ice calving from the
terminus of the
Perito Moreno Glacier in western
Patagonia, Argentina
Glacier
–
The
Aletsch Glacier, the largest glacier of the
Alps, in Switzerland
Glacier
–
The
Quelccaya Ice Cap is the largest glaciated area in the
tropics, in Peru
23.
Yosemite Valley
–
Yosemite Valley is a glacial valley in Yosemite National Park in the western Sierra Nevada mountains of Northern California. The valley is about 8 miles long and up to a deep, surrounded by high granite summits such as Half Dome and El Capitan. The valley is drained by the Merced River and a multitude of streams and waterfalls including Tenaya, Illilouette, Yosemite, Yosemite Falls is the highest waterfall in North America, and is a big attraction especially in the spring when the water flow is at its peak. The valley is renowned for its beauty, and is widely regarded as the centerpiece of Yosemite National Park. The Valley is the attraction in the park for the majority of visitors. On July 2,2011 there was a record 20,851 visitors to the valley, most visitors enter the valley from roads to the west and pass through the famous Tunnel View entrance. Visitor facilities are located in the center of the valley, there are both hiking trail loops that stay within the valley and trailheads that lead to higher elevations, all of which afford glimpses of the parks many scenic wonders. Yosemite Valley is located on the slope of the Sierra Nevada mountains,150 miles due east of San Francisco. It stretches for 7.5 miles in a roughly east-west direction, Yosemite Valley represents only one percent of the park area, but this is where most visitors arrive and stay. More than half a dozen creeks tumble from hanging valleys at the top of cliffs that can rise 3000–4000 feet above the valley floor. These streams combine into the Merced River, which flows out from the end of the valley. The flat floor of Yosemite Valley holds both forest and large meadows, which provide breathtaking views of the surrounding crests and waterfalls. The first view of Yosemite Valley many visitors see is the Tunnel View, so many paintings were made from a viewpoint nearby that the National Park Service named that viewpoint Artist Point. The view from the end of the Valley contains the great granite monolith El Capitan on the left. Just past this spot the Valley suddenly widens with the Cathedral Spires, to this point, the Valley has been curving gently to the left, to the north. Now a grand curve back to the right begins, with Yosemite Falls on the north, followed by the Royal Arches, opposite to the south is Glacier Point,3,200 feet above the Valley floor. At this point the Valley splits into two, one section slanting northeast, with the other curving from south to southeast, between them both, at the eastern end of the valley, is Half Dome, the most famous and most recognizable natural feature in the Sierra Nevada. Above and to the northeast of Half Dome is Clouds Rest, at 9926 feet, snow melting in the Sierra forms creeks and lakes
Yosemite Valley
–
Tunnel View
Yosemite Valley
–
Sentinel Rock at sunset
Yosemite Valley
Yosemite Valley
–
Yosemite Falls and
Half Dome in the winter
24.
Hanging valley
–
A valley is a low area between hills, often with a river running through it. In geology, a valley or dale is a depression that is longer than it is wide, the terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys. Most valleys belong to one of two main types or a mixture of them, with respect to the cross section of the slopes or hillsides. A valley in its broadest geographic sense is known as a dale. A valley through which a river runs may also be referred to as a vale, a small, secluded, and often wooded valley is known as a dell or in Scotland as a glen. A wide, flat valley through which a river runs is known in Scotland as a strath, a mountain cove is a small valley, closed at one or both ends, in the central or southern Appalachian Mountains which sometimes results from the erosion of a geologic window. A small valley surrounded by mountains or ridges is sometimes known as a hollow, a deep, narrow valley is known as a cwm. Similar geological structures, such as canyons, ravines, gorges, gullies, chines, a valley formed by erosion is called an erosional valley, a valley formed by geologic events such as drop faults or the rise of highlands is called a structural valley. A valley formed by flowing water, or river valley, is usually V-shaped, the exact shape will depend on the characteristics of the stream flowing through it. Rivers with steep gradients, as in mountain ranges, produce steep walls, shallower slopes may produce broader and gentler valleys. However, in the lowest stretch of a river, where it approaches its base level, it begins to deposit sediment, in prehistory, the rivers were used as a source of fresh water and food, as well as a place to wash and a sewer. The proximity of water moderated temperature extremes and provided a source for irrigation, most of the first civilizations developed from these river valley communities. In geography, a vale is a river valley, usually with a particularly wide flood plain or flat valley bottom. In Southern England, vales commonly occur between the escarpment slopes of pairs of chalk formations, where the dome has been eroded, exposing less resistant underlying rock. Rift valleys, such as the Albertine Rift, are formed by the expansion of the Earths crust due to tectonic activity beneath the Earths surface, there are various forms of valley associated with glaciation that may be referred to as glacial valleys. A valley carved by glaciers is normally U-shaped, the valley becomes visible upon the recession of the glacier that forms it. When the ice recedes or thaws, the remains, often littered with small boulders that were transported within the ice. Floor gradient does not affect the shape, it is the glaciers size that does
Hanging valley
–
Calchaquí Valleys in
Argentina
Hanging valley
–
U-shaped valley in
Glacier National Park,
Montana,
USA
Hanging valley
–
Romsdalen in
Western Norway is an almost vertical valley.
Hanging valley
–
Fljótsdalur in East
Iceland, a rather flat valley (in Scotland, this type of valley is called a "strath")
25.
Logarithmic scale
–
A logarithmic scale is a nonlinear scale used when there is a large range of quantities. Common uses include the strength, sound loudness, light intensity. It is based on orders of magnitude, rather than a linear scale. In particular our sense of hearing perceives equal ratios of frequencies as equal differences in pitch, the top left graph is linear in the X and Y axis, and the Y-axis ranges from 0 to 10. A base-10 log scale is used for the Y axis of the left graph. The top right graph uses a scale for just the X axis. A slide rule has logarithmic scales, and nomograms often employ logarithmic scales, the geometric mean of two numbers is midway between the numbers. Before the advent of graphics, logarithmic graph paper was a commonly used scientific tool. If both the vertical and horizontal axes of a plot are scaled logarithmically, the plot is referred to as a log–log plot, if only the ordinate or abscissa is scaled logarithmically, the plot is referred to as a semi-logarithmic plot. Bit Byte Decade John Napier Level Logarithm Logarithmic mean Preferred number Dehaene, Stanislas, Izard, Véronique, Spelke, Elizabeth, Pica, distinct intuitions of the number scale in Western and Amazonian indigene cultures. American Association for the Advancement of Science, why using logarithmic scale to display share prices
Logarithmic scale
–
Various scales: lin–lin,
lin–log, log–lin, and log–log. Plotted graphs are: y = 10 x (red), y = x (green), y = log e (x) (blue).
26.
Niagara Falls
–
They form the southern end of the Niagara Gorge. From largest to smallest, the three waterfalls are the Horseshoe Falls, the American Falls and the Bridal Veil Falls, the Horseshoe Falls lies on the border of the United States and Canada with the American Falls entirely on the American side, separated by Goat Island. The smaller Bridal Veil Falls are also on the American side, the international boundary line was originally drawn through Horseshoe Falls in 1819, but the boundary has long been in dispute due to natural erosion and construction. Located on the Niagara River, which drains Lake Erie into Lake Ontario, Horseshoe Falls is the most powerful waterfall in North America, as measured by vertical height and flow rate. The falls are 17 miles north-northwest of Buffalo, New York, while not exceptionally high, the Niagara Falls are very wide. More than six cubic feet of water falls over the crest line every minute in high flow. The Niagara Falls are famed both for their beauty and as a source of hydroelectric power. Balancing recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 19th century. The Horseshoe Falls drop about 188 feet, while the height of the American Falls varies between 70 and 100 feet because of the presence of giant boulders at its base. The larger Horseshoe Falls are about 2,600 feet wide, the distance between the American extremity of the Niagara Falls and the Canadian extremity is 3,409 feet. The volume of water approaching the falls during peak season may sometimes be as much as 225,000 cubic feet per second. The average annual rate is 85,000 cubic feet per second. Since the flow is a function of the Lake Erie water elevation. This is accomplished by employing a weir – the International Control Dam – with movable gates upstream from the Horseshoe Falls. The falls flow is further halved at night, and, during the low tourist season in the winter, water diversion is regulated by the 1950 Niagara Treaty and is administered by the International Niagara Board of Control. The current rate of erosion is approximately 1 foot per year and it is estimated that 50,000 years from now, even at this reduced rate of erosion, the remaining 20 miles to Lake Erie will have been undermined and the falls will cease to exist. The features that became Niagara Falls were created by the Wisconsin glaciation about 10,000 years ago, the same forces also created the North American Great Lakes and the Niagara River. All were dug by an ice sheet that drove through the area, deepening some river channels to form lakes
Niagara Falls
–
Niagara Falls
Niagara Falls
–
Louis Rémy Mignot, Niagara (Brooklyn Museum)
Niagara Falls
–
Niagara Falls, New York
Niagara Falls
–
American Falls (large waterfall on the left) and
Bridal Veil Falls (smaller waterfall on the right)
27.
Paulo Afonso Falls
–
Paulo Afonso Falls is a series of waterfalls on the São Francisco River in the north-east of Brazil adjacent to the city of Paulo Afonso. They stand up to 275 feet high, upstream of the falls, a hydroelectric dam, the Hidrelétrica de Angiquinho blocks the flow of the river. Prior to the damming of the river, the water flow over the falls was over 100,000 cu ft/s. The falls consist of a rapid that descends approximately 80 feet. The Paulo Afonso Hydroelectric Complex that grew from the plant was known as Complexo Hidrelétrico de Paulo Afonso in Portuguese. This, and later plants, such as the Hidrelétrica de Xingó downstream, near the town of Piranhas, Alagoas, provide much of the region with electric power
Paulo Afonso Falls
–
An 1850 painting of the falls
28.
Khone Falls
–
The Khone Falls and Pha Pheng Falls is a waterfall located in Champasak Province on the Mekong River in southern Laos, near the border with Cambodia. The Khone Falls are the largest in southeast Asia and they are the reason that the Mekong is not fully navigable into China. The falls are characterised by thousands of islands and countless waterways, the highest falls reach to 21 metres, the succession of rapids stretch 9.7 km of the rivers length. The average discharge of the cataract is nearly 11,000 m3/s, the Khone Falls is the prime reason why the Mekong river is not fully navigable into China. In the late 19th century French colonialists made repeated attempts to navigate the falls and this difficulty led to the construction of the Don Det – Don Khon narrow gauge railway on Don Det and Don Khon islands. Hillstream loach Hemimyzon khonensis is known from a specimen collected in the Mekong at the Khone Falls. The falls are home to the plabuck, a species of catfish said to be the largest freshwater fish in the world. The plabuck is alleged to reach lengths of 3 m and weights of up to 646 pounds, Mekong Express Laos Photo Album, Khone Falls Visit Laos, Champassak Province
Khone Falls
–
Khone Phapheng Falls
Khone Falls
Khone Falls
29.
Victoria Falls
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Victoria Falls, or Mosi-oa-Tunya, is a waterfall in southern Africa on the Zambezi River at the border of Zambia and Zimbabwe. It has been described by CNN as one of the Seven Natural Wonders of the world, Livingstone named his discovery in honour of Queen Victoria of Britain, but the indigenous Tonga name, Mosi-oa-Tunya—The Smoke That Thunders—continues in common usage as well. The World Heritage List officially recognizes both names, the nearby national park in Zambia is named Mosi-oa-Tunya, whereas the national park and town on the Zimbabwean shore are both named Victoria Falls. Victoria Falls is roughly twice the height of North Americas Niagara Falls, in height and width Victoria Falls is rivalled only by Argentina and Brazils Iguazu Falls. For a considerable distance upstream from the falls, the Zambezi flows over a sheet of basalt, in a shallow valley, bounded by low. The rivers course is dotted with numerous tree-covered islands, which increase in number as the approaches the falls. There are no mountains, escarpments, or deep valleys, only a flat plateau extending hundreds of kilometres in all directions. The falls are formed as the width of the river plummets in a single vertical drop into a transverse chasm 1708 metres wide. The depth of the chasm, called the First Gorge, varies from 80 metres at its end to 108 metres in the centre. At less than full flood, additional islets divide the curtain of water into separate parallel streams, the main streams are named, in order from Zimbabwe to Zambia, Devils Cataract, Main Falls, Rainbow Falls and the Eastern Cataract. The Zambezi river, upstream from the falls, experiences a rainy season from late November to early April, at full moon, a moonbow can be seen in the spray instead of the usual daylight rainbow. During the flood season, however, it is impossible to see the foot of the falls and most of its face, close to the edge of the cliff, spray shoots upward like inverted rain, especially at Zambias Knife-Edge Bridge. At this time it becomes possible to walk across some stretches of the river at the crest and it is also possible to walk to the bottom of the First Gorge at the Zimbabwean side. Water entering the Second Gorge makes a right turn and has carved out a deep pool there called the Boiling Pot. Reached via a footpath from the Zambian side, it is about 150 metres across. Its surface is smooth at low water, but at high water is marked by enormous, slow swirls and heavy boiling turbulence. Objects—and humans—that are swept over the falls, including the occasional hippopotamus or crocodile, are frequently found swirling about here or washed up at the north-east end of the Second Gorge. This is where the bodies of Mrs Moss and Mr Orchard, the recent geological history of Victoria Falls can be seen in the form of the gorges below the falls
Victoria Falls
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Victoria Falls
Victoria Falls
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David Livingstone gazing upon the Falls, in bronze, from the Zambian shore.
Victoria Falls
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First Gorge, from Zambian side
Victoria Falls
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Satellite image showing the broad Zambezi falling into the narrow cleft and subsequent series of zigzagging gorges (top of picture is north).
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Zambezi River
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The Zambezi is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. The area of its basin is 1,390,000 square kilometres, the Zambezis most noted feature is Victoria Falls. Other notable falls include the Chavuma Falls at the border between Zambia and Angola, and Ngonye Falls, near Sioma in Western Zambia, there is also a smaller power station at Victoria Falls. The area around the source is a monument, forest reserve. Eastward of the source, the watershed between the Congo and Zambezi basins is a belt of high ground, running nearly east-west. This distinctly cuts off the basin of the Lualaba from that of the Zambezi, in the neighborhood of the source the watershed is not as clearly defined, but the two river systems do not connect. The region drained by the Zambezi is a vast broken-edged plateau 900–1200 m high, composed in the interior of metamorphic beds. Coal is also found in the district just below Victoria Falls, gold-bearing rocks occur in several places. The river flows to the south-west into Angola for about 240 kilometres, then is joined by tributaries such as the Luena. It turns south and develops a floodplain, with extreme variation between the dry and rainy seasons. It enters dense evergreen Cryptosepalum dry forest, though on its western side, where it re-enters Zambia it is nearly 400 metres wide in the rainy season and flows rapidly, with rapids ending in the Chavuma Falls, where the river flows through a rocky fissure. The river drops about 400 metres in elevation from its source at 1,500 metres to the Chavuma Falls at 1,100 metres, in a distance of about 400 kilometres. From this point to the Victoria Falls, the level of the basin is very uniform, the first of its large tributaries to enter the Zambezi is the Kabompo River in the north-western province of Zambia. A major advantage of the Kabompo River was irrigation, civilization was built on farming, and the surplus of crops. The savanna through which the river has flowed gives way to a wide floodplain, a little farther south is the confluence with the Lungwebungu River. This is the beginning of the Barotse Floodplain, the most notable feature of the upper Zambezi, for more than 200 km downstream the annual flood cycle dominates the natural environment and human life, society and culture. Eighty kilometres further down, the Luanginga, which with its tributaries drains an area to the west. A few kilometres higher up on the east the main stream is joined in the season by overflow of the Luampa/Luena system
Zambezi River
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The Zambezi River at the junction of Namibia, Zambia, Zimbabwe and Botswana
Zambezi River
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Victoria Falls, the end of the upper Zambezi and beginning of the middle Zambezi
Zambezi River
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Annotated view of the Zambezi river delta from space.
Zambezi River
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The Zambezi's delta.
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Aerial view of Iguazu Falls on the Iguazu River between Brazil and Argentina
Aerial view of Rhine Falls in Switzerland
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This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "Catadupa". Cyclopædia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al. p. 169.
This article incorporates text from a publication now in the 
