Let's try to answer the following questions: - Embassy of Brazil in ...

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Let's try to answer the following questions: - Embassy of Brazil in ...

EmbraturIn this chapter we explore how some of Brazil's landforms were created.The vast country of Brazil is home to someof the largest and most impressive naturalfeatures in the world. This section will look atsome of those landforms and ask how theseBrazilian wonders have taken shape.Let's try to answer thefollowing questions:1 How was the mighty Amazon basin formed?2 What force creates the huge Iguaçu Falls?3 Why have Chile and Peru got volcanoes butBrazil hasn’t?4 What is the coast of Brazil like?AN AERIAL VIEW OF THE AMAZONEmbraturChapter 2: The Shaping of Brazil1


Water lilly on the amazonEmbraturcolourful MACAWEmbraturJosé MedeirosJosé Medeirosone of the many MONKEY speciesJAGUAR in the rainforestHow was the mighty Amazon basin formed?It’s difficult to overstate just how huge the Amazon River is. There is simply nothing else on theplanet that matches it for the colossal amount of water it contains or the enormity of the drainagebasin that flows into it.The distance from the source to the mouth of the Amazon is a phenomenal 6,577km. That’s alonger journey than the one between London and New York. Although the Amazon flows throughsome other countries in South America, over half of its length (some 3,615km) is in Brazil. Thismakes it vitally important for trade and transport – it’s possible to navigate an ocean-going steamersome 3,885km inland and reach Iquitos in Peru. The amount of water that the Amazon releasesinto the Atlantic Ocean is incredible. During the rainy season it can be as much as 300,000 cubicmetres every second. That’s more water than is held in some reservoirs – every second! Thismeans as much as one fifth of the world’s fresh water running into the oceans is from the Amazon.The mouth of the river, where it enters the Atlantic, is a staggering 330km wide. In fact, the width ofthe Amazon’s mouth is greater than the length of the entire route of the River Thames! It’s roughlythe same distance as the journey from Leeds to London in the United Kingdom.A “drainage basin” is the name given to all the land that drains rainfall into a river. Every riverhas a drainage basin, but the Amazon’s is the biggest in the world. An area of land covering6,915,000km² gathers water that ends up in the Amazon – that means as much as 40% of SouthAmerica drains water into this great river. The amazing Amazon drainage basin is 75% bigger thanthe entire continent of Europe!2 Schools’ Pack – Brazil 2009


If this information about the Amazon has amazed you, consider also the vast amount of wildlifethat the river is home to. There are 3,000 species of fish in the Amazonian waters and it is also themain habitat of the largest river dolphin, which can grow to 2.6m in length. The Amazon is also hometo the notorious piranha fish, which has developed a ferocious reputation as a flesh eater. Someattacks on humans have been reported, but experts say they are mainly interested in other fish.See for yourself: http://www.youtube.com/watch?v=UH3AQxrAT8k&feature=relatedThroughout the centuries the Amazon River has helped to shape the landscape by wearing awayhighlands, carving out a route through the country and depositing sediment out to sea. We will lookat how the Amazon has had an impact on the shape of the land by considering three processes:erosion, transportation and deposition.Erosion is a word that describes the wearing away of land by rain, rivers and wind. The powerof the Amazon has helped to remove earth, stones and rock from upland areas. This downwarderosion has helped to create some of the valleys that are visible in Brazil today.Once the material is eroded, it is transported – or moved - downstream by the force of the water.Finally, when the energy of the water lessens, the material is deposited. This basically means itis dropped off somewhere different at the end of its journey. Unlike other major rivers such as theMississippi or Nile, the Amazon does not have a delta. This is because the fast flowing river andocean current take the sediment far out to sea before it has a chance to settle and build up.Here are a few more facts about rivers in Brazil:With the exception of the Amazon (a big exception!), few of the larger Brazilian rivers are verygood for navigation.Many of the rivers flowing into Brazil’s Atlantic coast are very short and are broken bywaterfalls and rapids.The longest river that is wholly inside Brazil is the São Francisco. This flows over 1,600kmnorthward before turning east into the Atlantic. On its way it flows over the mighty PauloAfonso Falls.EmbraturEmbraturexceptionally easy navigationcascading WATERFALLChapter 2: The Shaping of Brazil3


DRAINAGE BASIN MAPWhat force creates the huge Iguacu Falls?EmbraturEmbraturthe powerful IGUAçU FALLSIGUAçU FALLS from the air4 Schools’ Pack – Brazil 2009


On the border between Brazil, Paraguay and Argentina there is an awesome series of waterfallscalled the Iguaçu Falls. There are 275 waterfalls in total, the biggest of which is 82m high.With 4.5 million litres of water cascading over the Iguaçu Falls every second, it’s even morespectacular than the famous 51m drop at Niagara Falls. Not surprisingly, Iguaçu Falls attractsthousands of tourists every year.The force that created Iguaçu Falls is actually the Paraná River that flows over it. The ferociouspower of the water has carved out deep pools, gorges and drops over thousands of years to makethe landscape appear as it does today.You can see how it happens in the diagram below. First the river flows over a layer of very hardrock called diabase or dolerite, which is above a layer of softer rock. When the water reaches agap in the hard rock it crashes down and starts to wear away the softer rock. As the soft rock iseaten away (1) there is nothing to support the hard rock above it so it falls down (2), helping to forma deep plunge pool below (3). The process starts all over again and so the water gradually forcesthe waterfall backwards (4). As it does this, it creates a steep-sided gorge (5) where the waterfallonce was.This happens very, very slowly. The edge of the hard rock only recedes by 3mm every year, whichjust shows how long the process has been taking place!FORMATION OF A WATERFALLChapter 2: The Shaping of Brazil5


Why have Chile and Peru gotvolcanoes and yet Brazil hasn't?Fortunately for Brazilians, the country is not ahotspot for volcanoes and earthquakes. Thereason for this is to be found in the map on theright, which shows how the crust of the earth isdivided up into what are called tectonic plates.These huge plates sit on top of molten rock –but the plates do not stay still. They are movingvery slowly, either colliding together or driftingapart. The place where two tectonic platesmeet is called a “plate boundary” and it’s herethat most earthquakes and volcanoes occur. Ifyou take another look at the map you will seethat Brazil sits right in the middle of the SouthAmerican Plate. As Brazil is not on top of anyplate boundaries, it is not known for volcanoand earthquake activity. Neighbouring Peruand Chile, however, are close to the boundarywith the Nazca Plate, which is why they havevolcanoes and earthquakes there.ATLANTIC PLATE TECTONICS MAPMAP OF RELIEF6 Schools’ Pack – Brazil 2009


There are several upland areas in Brazil, thelargest being the Brazilian Highlands thatdominate the south east of the country. Theedge facing the ocean, known as the GreatEscarpment, is very steep and high, rising fromsea level to 2,500m in some places.What is the coast of Brazil like?As there are more than 8,000km of coastline,it’s not surprising that the sea plays animportant role in the life of many Brazilians.Whether it’s for trade, housing, food, transportor leisure activities, the coastline is important tomillions of Brazilians. This section will give usan idea of what you might expect to find alongthe coast of Brazil.Rio de Janeiro, Sugar LoafEmbraturThe photograph on the right shows the city ofRio de Janeiro, which is on Brazil’s Atlanticcoast. Taken from an elevated position in thehighlands, the picture shows us the heavilybuilt-up city along with granite outcrops, one ofwhich forms the famous Sugarloaf Mountain.Rio de Janeiro, Barra da Tijuca neighbourhoodEmbraturIf we study the photograph in detail, we can learn a great deal about this part of the Brazilian coastline…It tells us that the mountains along the coast are very steep and drop down to the sea, leavingvery little flat land to build on or farm.Some of the mountains are isolated peaks, such as Sugarloaf Mountain. These are remnantsof ancient mountain ranges.At some points on the coast where the sea has created bays, important settlements and portshave developed.It is difficult to build roads from the coastal towns inland over the mountains and the areaknown as the Great Escarpment.This picture does not give an accurate pictureof all Brazil’s coast, however. North of Rio,between Salvador and Fortaleza, there is a verydifferent kind of coastline. Known as the GoldenCoast, this is a 3,480km stretch of beautifulbeaches. There are lively beaches with touristresorts, isolated beaches where you won’t seea soul, beautiful sand dunes and many varietiesof coloured sand.Jericoacoara dunes, near FortalezaEmbraturChapter 2: The Shaping of Brazil7

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