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APPSC - PRELIMS GEOGRAPHY WORLDGEOGRAPHY

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CONTENTS

Sl. No. TOPICS Pg. No.

GENERAL GEOGRAPHY

1. Our Universe ...... 7

2. Interior Infrastructure of Earth ...... 16

3. Mineral & Rocks ...... 21

4. Forces Effecting the Earth Movements ...... 25

5. Weathering & Erosion...... 27

6. Geogmorphological Landforms ...... 30

7. Volcanoes Earthquakes ...... 34

8. Erosional and Depositional Landforms...... 39

9. Drainage System & Patterns ...... 44

10. Atmosphere...... 46

11. Climatic Classification...... 58

12. Hydrosphere ...... 60

13. Soil...... 69 14. Natural Vegetatiowww.OnlineIAS.comn ...... 73 15. Population ...... 79

16. Human Settlement...... 84

17. Agriculture...... 89

18. Fisheries ...... 100

19. Minerals ...... 103

20. Industries...... 108

21. Energy Resources ...... 117

22. Transport ...... 122

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GENERAL GEOGRAPHY

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OUR UNIVERSE

Origin helium and heat and light is emitted. Thus a star is formed. When the hydrogen of a star is depleted, The big bang theory explains the origin of our its outer regions swell and redden. This stage of a universe. According to this theory, 15 billion years star is called a 'Red Giant'. Our sun will turn into ago, cosmic matter was in a compressed state from a 'Red Giant' in 5 billion years. 'Novae Stars' are which expansion started by a primordial stars whose brightness increases suddenly by 10 to explosion. The super-dense ball broke to form 20 magnitudes due to explosion and then the stars galaxies, which again broke to form stars and again fade into normal brightness. 'Super Novae' finally stars broke to form planets including earth. are stars whose brightness suddenly increases Since the outer space is limitless, conventional by more than 20 magnitudes. After the explosion, units for measuring distances are not suitable. the dense core of comparatively smaller stars is Hence new units as follows are used: called the 'white dwarf'. The dense core of the • Light Year: Distance covered by light in comparatively larger stars is called the one year in vacuum at a speed of 3x108 'Neutron star'. The neutron star rotates at a high m/s. One light year is equal to 9.46 × speed emitting radio waves. Such stars are called 1012 kilometers. 'Pulsar'. 'Black hole' stage of the star occurs when • Astronomical Unit: The Mean distance the ancient star collapses. Gravity becomes so between the Sun and the Earth (1.49 x intense in the hole that nothing escapes, even 8 10 km). One light year is equal to 60,000 light. AU. • Cosmic Year: Sun's period of revolution Constellations around the galactic centre (250 million years). Also called as 'galactic year' In the sky at night there are various patterns • Parsec: Distance at which the mean ra- formed by different groups of stars. These are dius of the Earth's orbit subtends an called constellations. Ursa Major or Big Bear is angle of one second of an arc. It is equal one such constellation. One of the most easily to 3.26 light years. recognizable constellations is the small bear or Saptarishi (Sapta-seven, Rishi-sages). It is a group of seven stars that forms a part of the large Ursa Galaxieswww.OnlineIAS.com Major Constellation. These are huge congregation of stars that hold Solar System together by force of gravity e.g. the Milky Way, Andromeda galaxy, large and small magellanic The sun along with its eight planets, asteroids cloud, Ursa Minor system, sculptor system, etc. and comets comprise the 'solar system'. The planets Milky Way or Akashganga is our home galaxy. are divided into inner or terrestrial planets which Our solar system is located in this galaxy. have higher densities e.g. Mercury, Venus, Earth and Mars and outer planets which have lower Stars densities e.g. Jupiter, Saturn, Uranus and Neptune. Stars are self luminous bodies that account for 98 percent of the matter in a galaxy. In the The Sun universe, some stars appear small but emit more energy than the other stars of the Milky Way. • The sun is in the center of the solar Such stars are called 'Quasars'. When the dense system. galactic nucleus is compressing to form a star, this • It is made up of extremely hot gases par- stage in star formation is called a 'protostar' stage. ticularly hydrogen. Due to high temperature hydrogen converts to • The sun is 109 times bigger than the

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earth and weighs 2 × 1027 tonnes. 45,000. 'Ceres' whose length is about 1000km is • The sun is about 150 million km away the largest one. They revolve around the sun in from the earth. The light from the sun the same way as the planets. reaches earth in about 8 minutes.

• The glowing surface of the sun is called Meteors and Meteorites 'Photosphere'. Above the 'Photosphere' The meteors are the remains of comets which is red coloured 'Chromosphere'. Beyond are scattered in the interplanetary space of the the Chromosphere is the 'Corona', vis- solar system. On contact with the earth's ible during eclipses. atmosphere, they burn due to friction. Those • The temperature of the photosphere is which completely burn out into ash are called about 6000°C and that of the Chromo- meteors or 'shooting star.' Those which do not sphere is about 32400°C, and that of the burn completely and strike the earth in the form corona about 2,700,000°C. The core of of rocks are called 'meteorites'. the sun has a temperature about 15 million degrees Kelvin. But that tremen- Planetary System dous heat is not felt so much by us be- cause despite being our nearest star, it is There are eight planets in our solar system. far away from us. They are: Mercury, Venus, Earth, Mars, Jupiter, • It takes 250 million years to complete Saturn, Uranus and Neptune. Earlier, Pluto was one revolution round its centre. This considered as a planet. But recently it has lost this period is called 'Cosmic year'. status. All the eight planets of the solar system • Sun spots' are dark patches notched on move around the sun in fixed paths. These paths the surface of the sun. They appear dark are elongated. They are called orbits. A new planet because they are cooler i.e. they have a 2003 UB 313 has been discovered recently in our temperature of about 1500°C. solar system. It is bigger than Pluto and farthest • The 'Aurora Borealis' or northern lights from the Sun. are multicoloured lights that sweep across the sky in waves and are visible A.Mercury in the arctic region. The 'Aurora Aus- 1. Mercury is the smallest and the nearest tralis' or southern lights are similarly planet to the Sun. visible near the Antarctica region. 2. It takes only about 88 days to complete The Moon one round along its orbit. • The moon is the only satellite of the earth. 3. It has no atmosphere and no satellite. • Its size is approximately one-fourth that 4. Its days are scorching hot and nights are of the earth. It has a diameter of 3475 frigid. km. • Its orbit is elliptical. The maximum dis- B.Venus tance (apogee) of the moon from the earth is 406,000 www.OnlineIAS.com km and the minimum 1. Venus is considered as 'Earth's-twin' distance (perigee) is 364,000 km. because its size and shape are very much similar to that of the earth. • The moon moves around the earth in about 27 days. It takes exactly the same 2. It is also called the 'morning' or 'evening star'. time to complete one spin. As a result, 3. It is probably the hottest planet because its only one side of the moon is visible to us atmosphere contains 90-95% of carbon on the earth. dioxide. The day and night temperatures • The bright parts of the moon are moun- are almost the same. tains whereas the dark patches are low- 4. The atmospheric pressure is 100 times that lying plains. of the earth. Asteroids 5. It has no satellite. Asteroids are a series of very small planets or fragments of planets lying between the orbit of Mars and that of Jupiter. They number about

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C. The Earth 270,000 km in diameter. 1. The earth is the third nearest planet to the 3. It has 21 known satellites. Among them Sun. Titan, Phobe, Tethys and Mimas are important. 2. In size, it is the fifth largest planet. 4. Its moon, Titan has nitrogen atmosphere 3. It is slightly flattened at the poles. That is why and hydrocarbons, the necessity of life but its shape is described as a Geoid. no life exists. 4. From the outer space, the earth appears blue because its two-thirds surface is G.Uranus covered by water. It is, therefore, called a blue 1. It is the only planet that lies on its side. planet. Hence, one pole or the other faces the sun as it orbits. D.Mars 2. It is one of the coldest planets because of 1. It is marked with dormant volcanoes and deep having an average temperature of -223?C. chasms where once water flowed. 3. Its atmosphere is made of mainly hydrogen. 2. It has a thin atmosphere comprising of The landscape is barren and there is frozen Nitrogen and Argon. methane cloud. 3. Beneath its atmosphere, Mars is barren, 4. There are 9 dark compact rings around the covered with pink soil and boulder. planet and a corkscrew shaped magnetic Because of this it is known as 'red planet'. field. 4. It has two satellite s namely 'Phobos' and 5. It has 15 satellites; prominent ones are 'Demos'. Aerial, Ambrial, Titania, Miranda etc. 5. The highest mountain here is Nix Olympia 6. It rotates north to south. which is three times higher than Mount Everest. H. Neptune 6. Recent explorations have thrown light on 1. It is the most distant planet from the sun. the possibility of existence of life here. 2. There are five rings of Neptune. The outer ring E. Jupiter seems to be studded with icy moonlets while the inner ring appears narrow and nearly 1. It is the largest planet of the solar system. solid. 2. Its atmosphere contains hydrogen, helium, 3. It has 8 satellites like Titron, Merid, N-1, methane and ammonia. N-2, N-3 etc. 3. It contains two and a half times the mass 4. Its atmosphere mostly contains of all the other planets combined. hydrocarbon compounds. The atmosphere 4. It reflects more than three times the energy appear blue, with quickly changing white it receives from thewww.OnlineIAS.com sun. icy methane clouds often suspended high 5. It has the great red spot which is an above an apparent surface. enormous eddy in the turbulent cloud cover. It also contains dusty rings and volcanoes. Pluto from Planet to Plutoid 6. It has 16 satellites like Ganymede, Aayo, Pluto, demoted from planet status in 2006, Europa, Callisto etc. got a consolation prize - it and other dwarf planets like it will be called plutoids. Plutoids are celestial F. Saturn bodies in orbit around the Sun at a distance 1. It is the second largest planet of the solar greater than that of Neptune that have sufficient system. mass for their hydrostatic equilibrium (near- spherical) shape. The two known plutoids are 2. It has a celebrated rings composed of Pluto and Eris. It is expected that more plutoids thousands of rippling, spiraling bands of will be named as science progresses and new icy rock and dust just 200 feet thick and discoveries are made.

www.OnlineIAS.com N. Kalyana Chakravarthy 8 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] (ii) A difference of 1 hour between two Motions of the Earth meridians which are 15°apart.

The earth has two main motions: (i) Rotation (iii) Deflection of ocean currents and winds. and (ii) Revolution. (iv) Rise and fall of tides every day The axis of the earth, which is an imaginary Revolution: It is earth's motion in its elliptical line, makes an angle of 66½° with its orbital plane. orbit around the sun. One revolution is completed

The plane formed by the orbit is known as the in 365 1/4 days, resulting in one extra day every orbital plane. The earth receives light from the fourth year. The year, consisting of 366 days is sun. Due to the spherical shape of the earth, only called a "leap year" having 29 days in the month of February. half of it gets light from the sun at a time. The portion facing the sun experiences day while the other half away from the sun experiences night.

The circle that divides the day from night on the globe is called the circle of illumination. This circle does not coincide with the axis as you see in the given figure.

Rotation: The earth rotates around its axis. The axis is an imaginary line passing through the centre of the earth. The earth completes one rotation in 23 hours, 56 minutes, 4.09 seconds to be exact. The earth rotates from west to east. The period of rotation is known as the earthday.

A year is usually divided into summer, winter,

spring and autumn seasons. Seasons change due to the change in the position of the earth around

the sun.

On 21st June, the Northern Hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. As a result, these

areas receive more heat. The areas near the poles receive less heat as the rays of the sun are slanting. The North Pole is inclined towards the sun and the

places beyond the Arctic Circle experience

continuous daylight for about six months. Since www.OnlineIAS.coma large portion of the Northern Hemisphere is

getting light from the sun, it is summer in the regions north of the equator. The longest day and the shortest night at these places occur on 21st June. At this time in the Southern Hemisphere all

these conditions are reversed. It is winter season there. The nights are longer than the days. This position of the earth is called the Summer

Solstice.

On 22nd December, the Tropic of Capricorn IAS receives direct rays of the sun as the South Pole tilts towards it. As the sun's rays fall vertically at the Tropic of Capricorn (23½° S), a larger portion Effects of the Rotation of the Earth of the Southern Hemisphere gets light. Therefore, (i) Causation of day and night

www.OnlineIAS.com N. Kalyana Chakravarthy 9 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] it is summer in the Southern Hemisphere with latitudinal angle. longer days and shorter nights. The reverse happens in the Northern Hemisphere. This Important Parallels of Latitude position of the earth is called the Winter Solstice. 1. Equator 0° On 21st March and September 23rd, direct 2. Tropic of Cancer 23 ½°N rays of the sun fall on the equator. At this position, neither of the poles is tilted towards the sun; so, 3. Tropic of Capricorn 23½°S the whole earth experiences equal days and equal 4. Arctic circle 66½°N nights. This is called an equinox. 5. Antarctic circle 66½°S On 23rd September, it is autumn season in Heat Zones of the Earth the Northern Hemisphere and spring season in the Southern Hemisphere. The opposite is the case The mid-day sun is exactly overhead at least on 21st March, when it is spring in the Northern once a year on all latitudes in between the Tropic Hemisphere and autumn in the Southern of Cancer and the Tropic of Capricorn. This area, Hemisphere. Thus, we find that there are days therefore, receives the maximum heat and is called and nights and changes in the seasons because of the Torrid Zone. the rotation and revolution of the earth respectively. The mid-day sun never shines overhead on any latitude beyond the Tropic of Cancer and the Some terminologies related to revolution are: Tropic of Capricorn. The angle of the sun's rays • Perihelion: The position of the earth goes on decreasing towards the poles. As such, when it is at its nearest point to the sun. the areas bounded by the Tropic of Cancer and the The earth reaches its perihelion on about Arctic Circle in the Northern Hemisphere, and the 3rd January at a distance of about 147 Tropic of Capricorn and the Antarctic Circle in million km from the sun. the Southern Hemisphere, have moderate • Aphelion: The position of the earth temperatures. These are, therefore, called when it is at its greatest distance from Temperate Zones. the sun. The earth reaches its aphelion on 4th July when it is at a distance of Areas lying between the Arctic Circle and the 152 million km from the sun. North Pole in the Northern Hemisphere and the • Perigee: The point in the orbit of the Antarctic Circle and the South Pole in the moon when it is nearest to the earth. Southern Hemisphere, are very cold. It is because • Apogee: The point in the orbit of the here the sun does not rise much above the moon when it is farthest from the earth. horizon. Therefore, its rays are always slanting. These are, therefore, called Frigid Zones. Effects of the Revolution of the Earth Great Circles: Any circle which divides a (i) Change of seasons. globe into hemispheres is a great circle. The (ii) Variation in the lengths of day and night equator is a great circle and Greenwich meridian at different times ofwww.OnlineIAS.com the year. together with meridian 180° make another great circle. The number of great circle is limitless. Great (iii) Shifting of wind belts. circle can extend in any direction: east to west, (iv) Determination of latitudes. north to south, north east to south west, and so on. Great circles are of equal length. Lattitude and Longitude Longitude: Latitude: The longitude shows the distance of a point Latitude of a place on the earth is the angular east or west of the Prime Meridian which is at 0° distance of the place from the equator. 1° of and passes through Greenwich, near London. For latitude is approximately equal to 111 km. each degree of longitude there is a difference of four minutes in time. Parallels of Latitude: They are circles drawn on the globe parallel to the equator. All the places Longitude and Time: The best means of on a parallel of latitude will have the same

www.OnlineIAS.com N. Kalyana Chakravarthy 10 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] measuring time is by the movement of the earth International Date Line: An imaginary and the moon. The sun regularly rises and sets zigzag line on the globe, approximately along the every day, and naturally, it is the best time-keeper 180° meridian of longitude. When a person throughout the world. crosses this line from East to West, he gains one day and when he crosses from West to East, he When the Prime Meridian has the sun at the loses one day. highest point in the sky, all the places along this meridian will have mid-day or noon. As the earth Solar Day: It is the time interval between rotates from west to east, those places east of successive crossings of the sun across the meridian Greenwich will be ahead of Greenwich time and of the celestial sphere of any fixed place in the those to the west will be behind it. The rate of same direction. This is equal to 24 hours. difference can be calculated as follows. The earth Sidereal Day: The period of rotation of the rotates 360° in about 24 hours, which means 15° an earth about its axis. This is calculated with respect hour or 1° in four minutes. Thus, when it is 12 to any fixed star. It is 4 minutes less than 24 hours. noon at Greenwich, the time at 15° east of Greenwich will be 15 × 4 = 60 minutes, i.e., 1 hour Solar Year (Tropical year): It is the average ahead of Greenwich time, which means 1 p.m. interval between successive returns of the sun in But at 15° west of Greenwich, the time will be its apparent motion along the ecliptic to a fixed behind Greenwich time by one hour, i.e., it will position on the celestial sphere of any fixed place. be 11.00 a.m. Similarly, at 180°, it will be midnight This is equal to 365.24 mean solar days. when it is 12 noon at Greenwich. Sidereal Year: The period of revolution of the Greenwich Mean Time: The local time at earth around the sun. It is calculated with Greenwich or any place on the Prime Meridian. reference to any fixed star. It is approximately All meridians to the east of Greenwich meridian equal to 365.26 days. have sunrise before that meridian. Local times To account for 1/4 of a day in a year, the leap along these meridians are therefore ahead of year system is adopted in the Gregorian G.M.T. Meridians to the west of Greenwich calendar. To account for the excess of 11 minutes meridian have sunrise after this meridian and in a year, the centurial year is considered a leap therefore their local times are behind G.M.T. year only when it is divisible by 400. Standard Time: A particular meridian of longitude passing through a country is chosen as Earth in Figures the reference meridian. The local time along this 1. Age 4,550 million years meridian, calculated with respect to Greenwich Mean Time in terms of its longitude is taken as the 2. Mass 5.976 × 1024 kg. Standard Time for that country. 3. Mean density 5.518 kg/litres.

Why do we have standard time? 4. Total Surface Area 510,000,000 km2. 5. Land Area 29.2% of the total The local times of places which are on different meridians are bound to differ.www.OnlineIAS.com For example, it will surface area. be difficult to prepare a time-table for trains which 6. Water Area 70.8% of the total cross several longitudes. In India, for instance, surface area. there will be a difference of about 1 hour and 45 minutes in the local times of Dwarka in Gujarat 7. Highest point and Dibrugarh in Assam. It is, therefore, necessary (Mt. Everest) 8,848 m to adopt the local time of some central meridian of a country as the standard time for the country. 8. Lowest point (Dead Sea) 397 m. Indian Standard Time: Time along 82 ½° E meridians, calculated with respect to G.M.T. 9. Greatest Ocean Depth 11,033 m India, for being a large country, is unusual in (Mariana Trench) having a single time zone all over the country. It 10. Mean Equatorial is 5½ hours ahead of G.M.T. Diameter 12,756 km.

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11. Equatorial the same everywhere. Elevation of land is circumference 40,076 km. measured from the level of the sea, which is taken as zero.

Theories of Origin of Earth The highest mountain peak Mt. Everest is 1. Buffon-Hypothesis: Based on sun-comet 8,848 metres above the sea level. The greatest collision. depth of 11,022 metres is recorded at Mariana Trench in the Pacific Ocean. 2. Kant-Gaseous Mass Theory: Based on Newton's law of gravitation. Continents 3. Chamberlain-Moulton: Planetesimal Hypothesis. There are seven major continents. These are separated by large water bodies. These continents 4. Jeans & Jeffery: Tidal Hypothesis: Based are - Asia, Europe, Africa, North America, South on sun-giant star attraction. America, Australia and Antarctica. 5. Alfven: Electromagnetic Hypothesis. Asia is the largest continent. It covers about 6. Russell and Littleton: Binary Star one-third of the total land area of the earth. The Hypothesis. continent lies in the Eastern Hemisphere. The 7. Ross-Gun-Fission Hypothesis: Rotational Tropic of Cancer passes through this continent. and Tidal hypothesis. Asia is separated from Europe by the Ural Mountains on the west. The combined landmass of 8. F. Hoyle: Super Nova Hypothesis. Europe and Asia is called the Eurasia (Europe 9. Big Bang Theory: Latest idea. + Asia).

Major domains of the earth Europe is much smaller than Asia. The continent lies to the west of Asia. The Arctic Circle Earth is the only planet which has life. passes through it. It is bound by water bodies on Human beings can live here because the life three sides. sustaining elements of land, water and air are present on the earth. The surface of the earth is a Africa is the second largest continent after complex zone in which three main components Asia. The Equator or 0° latitude runs almost of the environment meet, overlap and interact. through the middle of the continent. A large part The solid portion of the earth on which we live is of Africa lies in the Northern Hemisphere. It is the called the lithosphere. The gaseous layers that only continent through which the Tropic of surround the earth, is the atmosphere, where Cancer, the Equator and the Tropic of Capricorn oxygen, nitrogen, carbon dioxide and other gases pass. The Sahara Desert, the world's largest hot are found. Water covers a very big area of the desert, is located in Africa. The continent is bound earth's surface and this area is called the on all sides by oceans and seas. The world's longest river, the Nile, flows through Africa. hydrosphere. The hydrosphere comprises water in all its forms, that is, ice, water and water North America is the third largest continent of vapour. The biosphere iswww.OnlineIAS.com the narrow zone where the world. It is linked to South America by a very we find land, water and air together, which narrow strip of land called the Isthmus of contains all forms of life. Panama. The continent lies completely in the Northern and Western Hemisphere. Three oceans A. Lithosphere surround this continent.

The solid portion of the earth is called the South America lies mostly in the Southern lithosphere. It comprises the rocks of the earth's Hemisphere. The Andes, world's longest crust and the thin layers of soil that contain mountain range, runs through its length from nutrient elements which sustain organisms. There north to south. South America has the world's are two main divisions of the earth's surface. The largest river, the Amazon. large landmasses are known as the continents and the huge water bodies are called the ocean Australia is the smallest continent that lies basins. All the oceans of the world are connected entirely in the Southern Hemisphere. It is with one another. The level of seawater remains

www.OnlineIAS.com N. Kalyana Chakravarthy 12 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] surrounded on all sides by the oceans and seas. It The Indian Ocean is the only ocean named is called an island continent. after a country, that is, India. The shape of ocean is almost triangular. In the north, it is bound by Antarctica, completely in the Southern Asia, in the west by Africa and in the east by Hemisphere, is a huge continent. It is larger than Australia. the combined area of Europe and Australia. The South Pole lies almost at the centre of this The Arctic Ocean is located within the Arctic continent. As it is located in the South Polar Circle and surrounds the North Pole. It is Region, it is permanently covered with thick ice connected with the Pacific Ocean by a narrow sheets. There are no permanent human stretch of shallow water known as Bering Strait. settlements. Many countries have research It is bound by northern coasts of North America stations in Antarctica. India also has research and Eurasia. stations there. These are named as Maitri and Dakshin Gangotri. C. Atmosphere

The earth is surrounded by a layer of gas B. Hydrosphere called the atmosphere. This thin blanket of air is The earth is called the blue planet. More than an integral and important aspect of the planet. It 71 per cent of the earth is covered with water provides us with the air we breathe and protects and 29 per cent is with land. Hydrosphere consists us from the harmful effects of sun's rays. The of water in all its forms. As running water in atmosphere extends up to a height of about 1,600 oceans and rivers and in lakes, ice in glaciers, km. underground water and the water vapour in The atmosphere is divided into five layers atmosphere, all comprise the hydrosphere. More based on composition, temperature and other than 97% of the Earth's water is found in the properties. These layers starting from earth's oceans and is too salty for human use. A large surface are the troposphere, the stratosphere, the proportion of the rest of the water is in the form mesosphere, the thermosphere and the exosphere. of ice-sheets and glaciers or under the ground and a very small percentage is available as fresh water The atmosphere is composed mainly of for human use. nitrogen and oxygen, which make up about 99 per cent of clean, dry air. Nitrogen 78 per cent, Oceans oxygen 21 per cent and other gases like carbon dioxide, argon and others comprise 1% by volume. Oceans are the major part of hydrosphere. They are all interconnected. The ocean waters are The density of the atmosphere varies with always moving. The three chief movements of height. It is maximum at the sea level and ocean waters are the waves, the tides and the decreases rapidly as we go up. The climbers ocean currents. The four major oceans are the experience problems in breathing due to this Pacific Ocean, the Atlantic Ocean, the Indian decrease in the density of air. The temperature Ocean and the Arctic Ocean, in order of their size. also decreases as we go upwards.

The Pacific Ocean iswww.OnlineIAS.com the largest ocean. It is The atmosphere exerts pressure on the earth. spread over one-third of the earth. Mariana This varies from place to place. Some areas Trench, the deepest part of the earth, lies under experience high pressure and some areas low the Pacific Ocean. The Pacific Ocean is circular pressure. Air moves from high pressure to low in shape. Asia, Australia, North and South pressure. Moving air is known as wind. Americas surround it. D. Biosphere The Atlantic Ocean is the second largest Ocean in the world. It is 'S' shaped. It is flanked The biosphere is the narrow zone of contact by the North and South Americas on the western between the land, water and air. It is in this zone side, and Europe and Africa on the eastern side. that life exists. All the living organisms including The coastline of Atlantic Ocean is highly indented. humans are linked to each other and to the This irregular and indented coastline provides biosphere for survival. The organisms in the ideal location for natural harbours and ports. biosphere may broadly be divided into the plant From the point of view of commerce, it is the kingdom and the animal kingdom. busiest Ocean.

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The three domains of the earth interact with 12. A solar day is greater than a sidereal day each other and affect each other in some way or by 4 minutes. the other. For example, cutting of forests for 13. Each degree of latitude is equals to 111 km. fulfilling our needs of wood, or clearing land for 14. A person crossing International Date Line agriculture may lead to fast removal of soil from from the East to West loses one day. slopes. Similarly earth's surface may be changed 15. Mercury is the nearest planet to Sun. due to natural calamities like earthquakes or tsunamis. 16. Venus is the nearest planet to Earth. 17. Venus is the hottest planet; its atmosphere Discharge of waste material into lakes and contains 97% CO2. rivers makes the water unsuitable for human use. It also damages other forms of life. Emission from 18. Jupiter is the biggest planet. industries, thermal power plants and vehicles, 19. Venus is the brightest planet. pollute the air. Carbon dioxide (CO2) is an 20. Earth is the blue planet. important constituent of air. But increase in the 21. Mars is the Red planet. amount of CO2 leads to increase in global 22. Venus is the Morning and Evening Star. temperatures. This is termed as global warming. There is thus, a need to limit the use of resources 23. Pluto is the double planet. of the earth to maintain the balance of nature 24. Saturn and Uranus are known as the between the domains of the lithosphere, the planets with rings. atmosphere and the hydrosphere. 25. Mercury has the maximum diurnal range of temperature. Points to Remember 26. Saturn has maximum no. of satellites. 1. Mercury, Venus, Earth and Mars are 27. Pluto has the most eccentric orbit. known as' Inner Planets' whereas Jupiter, 28. Jupiter is the fastest rotating planet. Saturn, Uranus and Neptune are known as "Outer plants". 29. Venus is the slowest rotating planet. 2. Planets bigger than the earth are Jupiter, 30. Venus has the same period of rotation as Saturn, Uranus and Neptune. revolution. 3. Earth and Venus have almost same size, 31. The length of the day is nearly same on the hence these two are known as' Twin planet Mars as that of the Earth. planets" 32. Jupiter, Saturn, Uranus and Neptune are 4. All planets rotate in the same direction in the Jovian planets. which they revolve except Venus and 33. The angle of inclination of Mars is nearly Uranus. same as that of Earth. 5. Saturn is surrounded by three luminous, 34. Jupiter, Saturn, Uranus and Neptune are concentric rings. the outer planet. 6. Earth has the maximum density of 5.52 in 35. Mercury, Venus, Earth and Mars are the the solar system whilwww.OnlineIAS.come the Saturn has the least inner planets. density of 0.69. 36. Venus rotates from East to West. 7. According to gravity Jupiter stands first 37. Uranus rotates from North to South. followed by Neptune, Uranus, Saturn and 38. Mercury is the fastest revolving planet. Earth. 39. Pluto is the slowest revolving planet. 8. Mercury and Venus have no satellite. 40. Planet revolves around the sun in Anti- 9. Neptune's atmosphere has poisonous gases clockwise direction. like methane, ammonia, etc. 41. "Hydra" is the largest constellation. 10. Comets revolve around the Sun and when broken are converted into "Meteors". 42. The nearest galaxy. "Andromeda" is 22, 00,000 Light years away. 11. Earth is spherical in shape with compression at the poles and a bulge at 43. Existence of galaxies beyond Milky Way the equator. Hence earth is an oblate was first demonstrated by Edwin Hubble. spheroid or called a Geoid. 44. Galaxies are also called "Islands of universe"

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INTERIOR OF THE EARTH

The interior of the earth can be understood Scientists have estimated the values of only by indirect evidences as no one has reached temperature, pressure and the density of the interior of the earth. The surface materials at different depths. configuration of the earth is largely a product of Meteor is another source of information about the processes operating in its interior. A proper the interior of the earth. However, the material, understanding of the physiographic character that becomes available for analysis from meteors, of a region remains incomplete unless the effects is not from the interior of the earth. It is only of both endogenic processes as well as exogenic similar to that of the earth. Meteors are solid processes are studied. bodies developed out of materials same as, or similar to, earth. So, by analogy meteors provide Sources of information about the interior valuable information about the earth’s interior.

The earth’s radius is 6,370 km. Reaching the Other indirect sources include gravitation, centre of the earth and make observations or magnetic field and seismic activity. The collect samples of the materials is almost gravitational force is greater near the poles and impossible. Under such conditions, most of our less at the equator. It also differs according to the knowledge about the interior of the earth is mass of material. Thus the uneven distribution of largely based on analogies and inferences. Yet, material within the earth influences its value. The a part of the information is obtained through readings of the gravity, may, at places differ from direct observations and analysis of materials. the expected values. Such a difference is called gravity anomaly. Gravity anomalies give us Direct Sources information about the distribution of mass of the material in the crust of the earth. The readily available solid earth material is surface rock we get from mining areas. Besides Seismic/Earthquake Waves mining, scientists world over are working on two major projects such as “Deep Ocean Drilling The study of seismic waves provides a Project” and “Integrated Ocean Drilling complete picture of the layered interior. An Project”. The deepest drill at Kola, in Arctic earthquake in simple words is shaking of the Ocean, has so far reached a depth of 12 km. earth. It is a natural event. It is caused due to These drilling projectwww.OnlineIAS.coms have provided large release of energy, which generates waves that volume of information through the analysis of travel in all directions. The energy waves materials collected at different depths. Volcanic travelling in different directions reach the surface. eruption forms another source of obtaining Earthquake waves are basically of two types- direct information. As and when the magma body waves and surface waves. Body waves are comes out to the surface of the earth during generated due to the release of energy at the focus volcanic eruption it becomes available for and move in all directions travelling through the laboratory analysis. body of the earth. They interact with the surface rocks and generate new set of waves called Indirect Sources surface waves. These waves move along the Analysis of properties of rocks and magma surface. The velocity of waves changes as they indirectly provides information about the travel through materials with different densities. interior. Through mining we know that Denser the material, higher is the velocity. temperature and pressure increase with the There are two types of body waves. They are increasing depth. It is also known that the density called P and S-waves. P-waves move faster of the material also increases with depth.

www.OnlineIAS.com N. Kalyana Chakravarthy 15 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] and are the first to arrive at the surface. These are 105° and 140° from epicentre is identified as the also called ‘primary waves’. The P-waves are shadow zone of P-waves. However, the entire similar to sound waves. They travel through all zone beyond 105° does not receive S-waves. Thus materials gaseous, liquid and solid. S-waves arrive shadow zone of S-wave is much larger than that of at the surface with some time lag. These are called the P-waves. The shadow zone of P-waves secondary waves. S-waves can travel only appears as a band around the earth between 105° through solid materials. This characteristic of the S- and 140° away from the epicentre whereas that waves has helped scientists to understand the of S-wave is a continuous zone. structure of the interior of the earth. Structure of the interior Different waves travel in different manners. P-waves vibrate parallel to the direction of the Just like an onion, the earth is made up of wave. This exerts pressure on the material in the several concentric layers with one inside another. direction of the propagation. As a result, it The important zones include: creates density differences in the material leading The crust: The outer layer of the earth is to stretching and squeezing of the material. known as the crust. It comprises about 0.5% of the Other waves vibrate perpendicular to the earth’s body. Its thickness ranges from 5 to 40 km. direction of propagation. The direction of The crust is thicker beneath the continents than vibrations of S-waves is perpendicular to the beneath the oceans. It is made up of two layers: wave direction in the vertical plane. Hence, they upper lighter layer (density=2.7 g/cc) called create troughs and crests in the material medium the sial (silica + aluminium) and a lower denser through which they pass. Surface waves are layer (density=3.0 g/cc) called sima (silica considered to be the most damaging waves. + magnesium). The average density of the earth’s surface is less than 3 gm/c.c. The upper layer of Shadow Zone the crust is mainly com- posed of crystalline Earthquake waves are recorded in igneous and meta- morphic rocks, acidic in seismographs located at far off locations. nature. The lower layer of the crust contains However, there are certain areas where the basaltic & ultra-basic rocks. Conrad discontinuity waves are not reported. Such a separates the outer and the inner crusts.

The mantle: Below the crust of the earth is a thick

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layer called mantle. This layer extends upto a zone, where the waves are not recorded, is called depth of 2900 km. The mantle consists the ‘shadow zone’. The study reveals that for predominantly of solid olivine rocks made up of each earthquake, there exists an altogether silicates of magnesium and iron and displaying different shadow zone. Given figure shows the plastic properties. Its average density is 56.8. This shadow zones of P and S-waves. layer is separated from the crust by Mohorovicic

It was observed that seismographs, located Discontinu- ity. The outer and the inner mantle within 105° from the epicentre, recorded the are separated by another discontinuity named Repetti discontinuity. arrival of both P and S-waves. But, beyond 140° from epicentre, they record the arrival of P-waves, The core: Beyond a depth of 2900 km lies but not that of S-waves. Thus, a zone between the core of the earth. It is named as barysphere

www.OnlineIAS.com N. Kalyana Chakravarthy 16 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] and also nife (nickel and ferrous). Average the upper mantle there is a soft layer in which the thickness is 4671 kms. Average density is 17.2. mantle rock is at the temperature close to the By volume it constitutes 17% of the earth’s body. melting point. It sets in at an average depth of The temperature of the core is about 200°c. The about 80 km which is well below the base of the core is believed to be a reason for the earth’s continental crust. This layer is called as magnetism. It is separated from the mantle by “Aesthenosphere” and the rigid layer above it Gutenburg-Wiechert Discontinuity. is called as “lithosphere”. The aesthenosphere extends to a depth of about 400 km. Lithosphere & Aesthenosphere: Beneath

Composition and properties of different layers of the earth

Name of the Chemical Average Density Physical Properties layer Composition Thickness (g cm-3) (km) A.(i) Crust Sial 6 to 45 2.2 to 2.9 Solid part of lithosphere; partly molten under the

continents. (ii) Inner part of Outer silicate 45 to 100 The solid crust and lithosphere layer, Basaltic upper mantle B Aesthenosphere 50 to 400 It transmits both S- and P-wave but with

reduced velocities.

C.(i) Upper Mantle Sima (Peridotite 100 to 1700 3.1 to 4.75 Slightly solid and slightly plastic (mainly under iron- magnesium- material close to oceans) rich silicate rock) melting point. Transition zone of (ii) Lower Mantle Wholly Sima 1700 to2900 4.75 to 5.6 mixed metals and (Olivine- silicate Ultrabasic rocks) Liquid or in a plastic D.(i) Outer core Nife 2900 to 4980 9.9 - 12.3 state. Fe, Ni and S mixture. Iron and nickel. Solid (ii) Inner core www.OnlineIAS.comBarysphere (heavy 4980 to 6400 13.5 and rigid due to metallic rocks) tremendous overlying pressure.

Temperature: In upper 100 km the Composition of the Earth increase in temperature is estimated at the rate 1. Iron 35% of 12°C per km descend. In the next 300 km, the increase is of 2°C per km and below that 2. Oxygen 30% the rate of increase is 1°C per km. In the core 3. Silicon 15% the temperature is about 2000°C. But at the 4. Magnesium 13% same time there is a huge pressure of overlying layers of the earth’s interior. So even under 5. Nickel 2.4% extremely high temperature towards the 6. Sulphur 1.9% central part of the earth the liquid nature of the earth core has acquired the properties of a 7. Calcium 1.1% solid and is probably in a plastic state. 8. Aluminium 1.1% www.OnlineIAS.com N. Kalyana Chakravarthy 17 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected]

Continental drift called “aesthenosphere” and carry the continents and oceans on their back. The edges The theory of continental drift, expounded of the plates are designed as boundaries and by Alfred Wegener in 1915, holds that portions margins, where movements occur. of the original continent which comprised the entire landmass of the world underwent a series Major plates of the world are: of horizontal displacement before the present 1. American plate continents were formed. 2. Pacific plate According to this theory, about 280 million 3. Antarctic plate years ago, the entire landmass formed one super 4. African plate continent, called Pangea. According to 5. European plate and Wegener, after the breaking of the super 6. Australian plate. continent pangae, the movement of the Some minor plates are: continents took place in two directions- one towards the equator due to centrifugal force of the 1. Caribbean plate. earth which gave rise to fold mountains like the 2. Cocas plate Himalayas, the alps, etc. and another towards 3. Nazca plate west due to tidal force of sun and the moon which 4. Juan de Fuca plate gave rise to Andes and Rockies. 5. Philippine plate, etc.

A glance at the world map shows that S. All these plates are in constant motion both America particularly Brazil can be fitted into the in relation to each other and with regard to the Gulf of Guinea of Africa; Antarctica can roughly be earth’s motion. Some movements are responsible fitted into S. Australian coast and S.E-African for the volcanic activities, seismic and other plate coast. Similarly NW-Australian coast and E- disturbances on the margins of the plates.

Indian coast are liable to fit. After the drifts some Types of movements of plates water bodies developed between them. Geological evidences prove that S. America and Africa were A. Convergence: When the oceanic probably joined together till the upper Triassic. lithosphere moves towards the continental Biological history of certain animals like lithosphere, due to its thickness the continental marsupials and placental mammals also throw crust is unable to go down and it is the oceanic significant light on the continental drift. crust which is involved in subduction. The downwent plate of the oceanic crust melts and

produces magma. This magma rises

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slowly and emerges as intrusive igneous rock in

the form of volcanic mountains on the continental crust. Thus origin of volcanic Plate Tectonics mountains like Andes takes place.

Plate tectonics deals with rock structures which are in the form of the plates and it is not only the continents which are in motion but the oceansIAS as well. These plates include not only the earth’s upper crust but also the part of denser mantle below. They have an average thickness of 100 km. They float on the plastic upper mantle

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When the two oceanic lithospheres lie on also termed as “ocean floor spreading”. Deep both side of subduction, then either of the two beneath the continental plate a column of heated plates may subduct. The subducted part melts mantle rock begins to rise and reach the plate and the magma rises above the oceanic surface above, causing the plate to fracture, which is called “continental rupture”. At first block and volcanic islands are formed in arc form like Aleutian island, Kuril Island, Ryuku Island, etc. mountains are formed. Next a long narrow valley called “rift valley” appears. The widening crack When the continental lithosphere lies on in its center is continuously filled in with magma both sides of subduction, the sediments get rising from the mantle below. The magma scrapped off the descending plate margin. In the solidifies to form new crust and also a new next stage the two continents collide, squeezing oceanic crust and lithosphere. the sediment mass and throwing it into complicated fold and high alpine ranges like C. Parallel movements of plates: Parallel

Himalayas and Alps are formed. plates, as they slide past each other along a

common boundary, do not create a new crust B. Divergence/continental rupturing: It is or destroy the old one but they produce “transform faults” which are fractures in rock

formation. Fractures imply displacement of rocks. As the plates continue to move, the locked rocks snap. They shift violently back to

equilibrium like a bent - stick breaking. This violent shift causes earth - quakes.

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MINERALS & ROCKS

magnesium, iron and silica. Pyroxene forms 10 Minerals per cent of the earth’s crust. It is commonly found in meteorites. It is in green or black colour. A mineral is a naturally occurring substance that is solid and stable at room temperature, • Amphibole representable by a chemical formula, usually Aluminium, calcium, silica, iron, magnesium abiogenic, and has an ordered atomic structure are the major elements of amphiboles. They form 7 per cent of the earth’s crust. It is in green or Mineral are divided as follows: black colour and is used in asbestos industry. Hornblende is another form of amphiboles. A. Metallic Minerals • Mica It comprises of potassium, aluminium, These minerals contain metal content and magnesium, iron, silica etc. It forms 4% of the can be sub-divided into three types: earth’s crust. Commonly found in igneous and (i) Precious metals: gold, silver, platinum etc. metamorphic rocks, it is used in electrical (ii) Ferrous metals: iron and other metals often instruments. mixed with iron to form various kinds of • Olivine steel. Magnesium, iron and silica are major (iii) Non-ferrous metals: include metals like elements of olivine. It is used in jewellery. It is copper, lead, zinc, tin, aluminium etc. usually a greenish crystal, often found in basaltic rocks. Other minerals like chlorite, calcite, B. Non-Metallic Minerals magnetite, haematite, bauxite and barite are also present in some quantities in the rocks. These minerals do not contain metal content. Sulphur, phosphates and nitrates are examples of Rocks non-metallic minerals. Cement is a mixture of non-metallic minerals. The earth’s crust is composed of rocks. A rock is an aggregate of one or more minerals. Some Major Minerals and Their Characteristics Rock may be hard or soft and in varied colours. • Feldspar For example, granite is hard, sandstone is soft. Gabbro is black and quartzite can be milky white. Silicon and oxygen are common elements in Rocks do not have definite composition of all types of feldspar and sodium, potassium, www.OnlineIAS.commineral constituents. Feldspar and quartz are the calcium, aluminium etc. are found in specific most common minerals found in rocks. feldspar variety. Half of the earth’s crust is composed of feldspar. It has cream to salmon The crustal rocks are classified on the basis pink colour. It is used in ceramics industries. of mode of formation, physical and chemical

properties, location etc. On the basis of mode of • Quartz formation the rocks are divided into three It is one of the most important components of categories (i) igneous rocks (ii) sedimentary sand and granite. It consists of silica. It is a hard rocks (iii) metamorphic rocks. mineral virtually insoluble in water. It is white or colourless and used in radio and radar. It is one A) Igneous rocks of the most important components of granite. As igneous rocks form out of magma and • Pyroxene lava from the interior of the earth, they are Pyroxene consists of calcium, aluminum, known as primary rocks. The igneous rocks are

www.OnlineIAS.com N. Kalyana Chakravarthy 20 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] formed when magma cools and solidifies. When (ii) Extrusive igneous rocks are formed due magma in its upward movement cools and turns to cooling and solidification of hot and molten into solid form it is called igneous rock. The lava at the earth’s surface e.g. Basalt, Gabbro, process of cooling and solidification can happen obsidian. in the earth’s crust or on the surface of the earth. B) Sedimentary rocks Igneous rocks are characterized on the basis of texture. Texture depends upon size and The word ‘sedimentary’ is derived from the arrangement of grains or other physical Latin word sedimentum, which means settling. conditions of the materials. If molten material is Rocks (igneous, sedimentary and metamorphic) cooled slowly at great depths, mineral grains may of the earth’s surface are exposed to be very large. Sudden cooling (at the surface) denudational agents, and are broken up into results in small and smooth grains. Intermediate various sizes of fragments. Such fragments are conditions of cooling would result in transported by different exogenous agencies and intermediate sizes of grains making up igneous deposited. These deposits through compaction rocks. Granite, gabbro, pegmatite, basalt, turn into rocks. This process is called lithification. volcanic breccia and tuff are some of the In many sedimentary rocks, the layers of examples of igneous rocks. deposits retain their characteristics even after lithification. Hence, we see a number of layers Igneous rocks are roughly hard rocks and of varying thickness in sedimentary rocks like water percolates with great difficulty. They do sandstone, shale etc. not have strata and are less affected by chemical weathering. They don’t contain fossils. The Depending upon the mode of formation, number of joints increases upwards. They are sedimentary rocks are classified into three major mostly associated with volcanic activity. groups: (i) mechanically formed - e.g. sandstone, conglomerate, shale, loess etc. (ii) organically They are classified on several grounds as formed - e.g. chalk, limestone, coal etc. (iii) mentioned below: chemically formed – e.g. chert, halite, potash etc.

(a) On the basis of silica content: These rocks are formed due to aggregation (i) Acidic igneous rocks have more silica e.g. and compaction of sediments. These rocks Granites contain fossils of plants and animals. They cover 75 percent of surface area of the globe. However (ii) Basic igneous rocks have less silica e.g. they form only 5 percent of the volume of earth’s Gabbro. crust. They contain several layers or strata but

these are seldom crystalline rocks. They are (b) On the basis of chemistry and seldom found in original and horizontal manner. mineralogical composition: They may be well consolidated, poorly (i) Felsic igneous rock (feldspar is dominant) consolidated and even unconsolidated. They are (ii) Mafic igneous rock (magnesium and ferrous characterized by different sizes of joints. Most sedimentary rocks are porous and permeable. are dominant) www.OnlineIAS.com (iii) Ultra mafic igneous rock (Peridotite and The formation of sedimentary rocks takes place dunite are dominant). in three stages:

• Transportation: after weathering and (c) On the mode of occurrence: erosion the fragments of parental rocks are (i) Intrusive igneous rocks— they are transported by the agents of erosion like cooled and solidified below the surface of the stream, wind, air, etc. earth. They are further divided into plutonic and • Deposition: transported materials are hypabyssal igneous rocks. Plutonic rocks cool deposited in sea, lakes, etc. The particles deep beneath the earth e.g. Granite. Hypabyssal are deposited in parallel layers and their rocks cool just beneath the earth surface e.g. process of layer formation is called Batholith, laccolith, phacolith, lapolith, sills, “stratification”. dykes, etc. • Consolidation: when the number of layer

www.OnlineIAS.com N. Kalyana Chakravarthy 21 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] is large, the weight of upper layer begins to affect In regional metamorphism, rocks undergo the lower layers and the further compression recrystallization due to deformation caused by solidifies the sediments into rocks. tectonic shearing together with high temperature or pressure or both. In the process of They are classified under different schemes: metamorphism in some rocks grains or minerals get arranged in layers or lines. Such an 1. On the basis of nature of sediments: arrangement of minerals or grains in metamorphic rocks is called foliation or lineation. (a) Mechanically formed or clastic rocks e.g. Sandstones. Conglomerates, clay rock, Sometimes minerals or materials of different shale, loess. groups are arranged into alternating thin to thick layers appearing in light and dark shades. Such (b) Chemically formed sedimentary rocks e.g. a structure in metamorphic rocks is called gypsum, salt rock. banding and rocks displaying banding are called (c) Organically formed sedimentary rocks e.g. banded rocks. Types of metamorphic rocks Limestone, dolomites, coal, peats, etc. depend upon original rocks that were subjected to metamorphism. 2. On the basis of transporting agents: Metamorphic rocks undergo complete (i) Argillaceous or aqueous rocks: (a) Marine alteration in the appearance of pre-existing rocks rocks, (b) Lacustrine rocks, (c) Riverine due to change in mineral composition and texture rocks through temperature and pressure changes. (ii) Aeolian rocks e.g. Loess. Gneiss, granite, slate, schist, marble, quartzite etc. (iii) Glacial sedimentary rocks e.g. Till, moraine. are some examples of metamorphic rocks. They are classified as mentioned below:

C). Metamorphic rocks 1. Contact or thermal metamorphism: here The word metamorphic means ‘change of metamorphism occurs when the mineral form’. These rocks form under the action of composition of the surrounding rocks is changed pressure, volume and temperature (PVT) due to intense heat e.g. Limestone is changed to changes. Metamorphism occurs when rocks are marble. forced down to earth’s interior by tectonic 2. Regional or dynamic metamorphism: processes or when molten magma rising through here pressure plays an important role so that the crust comes in contact with the crustal rocks rocks are altered in their forms in an extensive or the underlying rocks are subjected to great area. amounts of pressure by overlying rocks. Metamorphism is a process by which already Rock Cycle consolidated rocks undergo recrystallization and reorganization of materials within original rocks. Rocks do not remain in their original form for long but may undergo transformation. Rock cycle Mechanical disruptiowww.OnlineIAS.comn and reorganization is a continuous process through which old rocks of the original minerals within rocks due to are transformed into new ones. Igneous rocks breaking and crushing without any appreciable are primary rocks and other rocks chemical changes is called dynamic (sedimentary and metamorphic) form from these metamorphism. The materials of rocks primary rocks. Igneous rocks can be changed chemically alter and recrystallize due to thermal into metamorphic rocks. The fragments derived metamorphism. There are two types of thermal out of igneous and metamorphic rocks transform metamorphism - contact metamorphism and into sedimentary rocks. Sedimentary rocks regional metamorphism. themselves can turn into fragments and the In contact metamorphism the rocks come in fragments can be a source for formation of other contact with hot intruding magma and lava and sedimentary rocks. The crustal rocks (igneous, the rock materials recrystallize under high metamorphic and sedimentary) once formed temperatures. Quite often new materials form may be carried down into the mantle (interior out of magma or lava are added to the rocks. of the earth) through subduction process (parts

www.OnlineIAS.com N. Kalyana Chakravarthy 22 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] or whole of crustal plates going down under another plate in zones of plate convergence). The same can melt down due to increase in temperature in the interior and turn into molten magma, the original source for igneous rocks.

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FORCES EFFECTING THE EARTH MOVEMENTS

The forces which affect the earth’s (syncline) as a result of horizontal earth movement are involved in the creation, movements which cause compression within the destruction, recreation and maintenance of crust. The anticlines of the folds generally form various types of relief features of varying the mountains and the adjacent synclines form magnitudes. On the basis of origin these forces the valleys. Most of the mountain ranges of the are divided into (i) endogenetic forces and (ii) world consist of Fold Mountains e.g. the Alps, the exogenetic forces. While endogenetic forces Andes, the Rockies and the Himalayas. create relief features on the earth’s surface, the exogenetic forces through their erosional and Geometry of Folds - Folds are described by depositional activities destroy them and help in their form and orientation. The sides of a fold the planation process. are called limbs. The limbs intersect at the tightest part of the fold, called the hinge. A line Endogenetic forces connecting all points on the hinge is called the fold axis. In the diagrams above, the fold axes are Term endogenic refers to internal processes horizontal, but if the fold axis is not and phenomena that occur beneath the Earth's horizontal the fold is called a plunging surface. These forces are divided into sudden forces and diastrophic forces.

(a) Sudden forces: events like earthquake and volcanic eruption occur suddenly and the

resultant forces work very quickly. They are constructive forces as they create cones, lakes, plateaus, lava plains etc.

(b) Diastrophic forces: they include both vertical and horizontal movements.

(i) Vertical movement: they include emergence and subsidence of land masses. Emergence may occur due to upliftment of fold and the angle that the fold axis makes with the whole continent or part there of or a horizontal line is called the plunge of the fold. upliftment of coastawww.OnlineIAS.coml land of the continents. An imaginary plane, that includes the fold axis Submergence may occur when the land and divides the fold as symmetrically as possible, near the sea coast subsides below sea level. is called the axial plane of the fold.

(ii) Horizontal movement: these forces work Types of Folds into two ways a) In opposite direction - this includes Not all folds are equal on both sides of the tensional or divergent forces which create axis of the fold. Those with limbs of relatively faults, rupture, fracture, cracks etc. equal length are termed symmetrical, and those b) Towards each other - This includes with highly unequal limbs are asymmetrical. compressional or convergent forces which Asymmetrical folds generally have an axis at an create folding, warping etc. angle to the original unfolded surface they formed on. Other kinds of folds are: Folding: • Anticlines - Up folds.

It is the process whereby the rock strata are When the upper part of the fold is eroded bent into a series of arches (anticlines) and toughs away, the oldest rocks are in the center of the fold, and the youngest rocks are on

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each side. Also, the rocks dip (or slope) by the sinking of a block of land between two away from the central axis of the fold. more or less parallel faults. Examples: East African rift valley, Narmada and Tapti valleys. • Synclines - Down folds. Columns of faulting bring four distinguishable When the upper part of the fold is eroded away, the youngest rocks are in the center landforms as: of the fold, and the oldest rocks are on I. Rift valley: it is the result of the subsidence of

each side. Also, the rocks dip toward the the central column. When the central central axis of the fold. column of the two fault-lines subsides, the rift valley is made. "Damodar valley" is such an • Monoclines - a bend in otherwise horizontal strata. example. II. Ramp valley: when both side columns are • Isoclinal folds have undergone greater stress that has compressed the limbs of the raised and the central column is standstill, folds tightly together. then the made landform is ramp valley. "Brahmaputra" river passes through a ramp • The limbs of overturned folds dip in the valley. same direction, indicating that the upper part of the fold has overridden the lower part. III. Block Mountain: this is the result of the

Depending subsidence of side column. The central column gets

steep rim along the fault scarps and the on where the exposure is in an overturned raised landform is Block Mountain. fold, the oldest strata might actually be on top "Satpura hills" of India is such an example. of the sequence and be misinterpreted as IV. Horst: Horst is a similar landform but is the youngest rock unit. supposed to be due to upward force from beneath the central column. Side-columns • Recumbent folds, found in areas of the greatest tectonic stress,www.OnlineIAS.com are folds that are are standstill. "Harz Mountain" of Germany is an example. so overturned that the limbs are essentially horizontal and parallel. Exogenetic forces • Chevron: angular fold with straight limbs and small hinges. Exogenic forces refer to external processes and phenomena that occur on or above the Faulting: Earth's surface. Comet and meteoroid impacts, the tidal force of the moon and sun's radiations It is the process by which the tensional earth are all exogenic. Weathering effects and erosion movements under the effect of considerable are also exogenic processes. They also affect the pressure create a fracture in the earth's crust. planation processes. These are also called Faulting gives rise to relief features like block denudational or destructive forces. The erosional mountains (horsts), rift valleys, etc. A rift valley is process is affected by running water, ground a long, relatively narrow depression formed water, glaciers, sea waves etc. These processes form erosional and depositional land forms.

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melting. This process is most effective at Weathering high elevations in mid-latitudes where Weathering is the process of disintegration freezing and melting is often repeated. and decomposition of rocks while erosion is the Glacial areas are subject to frost wedging process of removal, transportation and daily. In this process, the rate of freezing is deposition of the weathered particles. These important. Rapid freezing of water causes processes together are known as “Denudation.” its sudden expansion and high pressure.

Weathering is defined as mechanical The resulting expansion affects joints, cracks disintegration and chemical decomposition of and small inter granular fractures to rocks through the actions of various elements of become wider and wider till the rock breaks weather and climate. Weathering process brings apart. mechanical disintegration and chemical (b) Thermal Expansion and Contraction: decaying of rocks. Weather conditions are the Various minerals in rocks possess their own most decisive phenomenon hence the name limits of expansion and contraction. With rise weathering. However the type and rate of in temperature, every mineral expands and weathering are also influenced by rock structure, pushes against its neighbour and as topography and vegetation. Weathering is a temperature falls, a corresponding static process. It is also the process of soil genesis. contraction takes place. Because of diurnal It is of three types: changes in the temperatures, this internal

I. Mechanical Weathering: When a region movement among the mineral grains of the undergoes mechanical weathering, rocks are superficial layers of rocks takes place broken into small pieces. Physical or mechanical regularly. This process is most effective in weathering processes depend on some applied dry climates and high elevations where forces. The applied forces could be: (i) diurnal temperature changes are drastic. gravitational forces such as overburden pressure, Though these movements are very small load and shearing stress; (ii) expansion forces they make the rocks weak due to continued due to temperature changes, crystal growth or fatigue. animal activity; (iii) water pressures controlled The surface layers of the rocks tend to by wetting and drying cycles. expand more than the rock at depth and this leads to the formation of stress within the Many of these forces are applied both at the www.OnlineIAS.comrock resulting in heaving and fracturing surface and within different earth materials parallel to the surface. Due to differential leading to rock fracture. Most of the physical heating, the resulting expansion and weathering processes are caused by thermal contraction of surface layers and their expansion and pressure release. These processes subsequent exfoliation from the surface are small and slow but can cause great damage results in smooth rounded surfaces of rocks. to the rocks because of continued fatigue the rocks suffer due to repetition of contraction and In rocks like granites, smooth surfaced and expansion. rounded small to big boulders called tors form due to such exfoliation. In the area of This mechanical disintegration takes place in hot deserts, the diurnal range of different ways. temperature brings the expansion and contraction of surface rocks, leading to their (a) Frost Action: Frost weathering occurs due disintegration into smaller pieces. to growth of ice within pores and cracks of rocks during repeated cycles of freezing and (c) Exfoliation: This is the expansion by

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unloading process. Unloading occurs when (i) Flaking: Different heating of outer and large igneous bodies are exposed through lower shells of a rock mass causes flaking. the erosional removal of overlying rock and II. Chemical Weathering: It changes the basic the reduction in the pressure. On being properties of the rock. Principal processes exposed to the surface they expand slightly in of chemical weathering are: volume. This leads to the peeling of thick (a) Solution: Here the rocks are completely shells like an onion’s layers from the parent dissolved. This process involves removal of rock. solids in solution and depends upon (d) Spalling: When there is a sudden shower solubility of a mineral in water or weak in the hot desert area, the highly heated acids. rocks when struck by sudden drizzle On coming in contact with water many develop numerous cracks. solids disintegrate and mix up as suspension (e) Cavernous Weathering: It occurs generally in water. Soluble rock forming minerals like in hot arid region and also in the rocks of nitrates, sulphates and potassium etc. are coastal area. affected by this process. So, these minerals are (f) Salt Weathering: Salts in rocks expand due easily leached out without leaving any to thermal action, hydration and residue in rainy climates and accumulate crystallization. Many salts like calcium, in dry regions. Minerals like calcium sodium, magnesium, potassium and barium carbonate and calcium magnesium have a tendency to expand. Expansion of bicarbonate present in limestones are these salts depends on temperature and soluble in water containing carbonic acid their thermal properties. High temperature (formed with the addition of carbon dioxide ranges between 30°C and 50°C of surface in water), and are carried away in water temperatures in deserts favour such salt as solution. Carbon dioxide produced by expansion. decaying organic matter along with soil water greatly aids in this reaction. Common Salt crystals in near-surface pores cause salt (sodium chloride) is also a rock forming splitting of individual grains within rocks, mineral and is susceptible to this process of which eventually fall off. This process of solution. falling off of individual grains may result in granular disintegration or granular (b) Oxidation and Reduction: In weathering, foliation. oxidation means a combination of a mineral with oxygen to form oxides or Salt crystallization is most effective of all salt- hydroxides. Oxidation occurs where there weathering processes. In areas with is ready access to the atmosphere and alternating wetting and drying conditions oxygenated waters. The minerals most salt crystal growth is favoured and the commonly involved in this process are iron, neighbouring grains are pushed aside. manganese, sulphur etc. Though it is a Sodium chloride and gypsum crystals in universal phenomenon but it is more desert areas heave up overlying layers of apparent in rocks containing iron. materials and witwww.OnlineIAS.comh the result polygonal cracks develop all over the heaved surface. In the process of oxidation rock breakdown With salt crystal growth, chalk breaks down occurs due to the disturbance caused by most readily, followed by limestone, addition of oxygen. Red colour of iron upon sandstone, shale, gneiss and granite etc. oxidation turns to brown or yellow. When oxidized minerals are placed in an (g) Sheeting: The development of cracks and environment where oxygen is absent, fractures, parallel to the ground surface, reduction takes place. Such conditions exist caused by removal of superincumbent load. usually below the water table, in areas of (h) Cambering process: Due to expansion stagnant water and waterlogged ground. caused by unloading of super-incombitant Red colour of iron upon reduction turns to load and consequent release of confining greenish or bluish grey. pressure. (c) Hydration: Hydration is the chemical

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addition of water. Most of the rock-forming move materials to or near the surface where minerals absorb water. Minerals take up they are more closely subjected to chemical water and expand. This not only increases weathering.

their volume but also produces chemical Erosion changes resulting in the formation of new minerals which are softer and more Erosion is concerned with the various ways in voluminous. E.g. this process converts which the mobile agencies acquire and remove hematite into limonite. Calcium sulphate rock debris. The acquisition of materials by the takes in water and turns to gypsum, which mobile agencies and their transport, i.e. corrasion is more unstable than calcium sulphate. and transportation are considered to be the This process is reversible and long, integral part of erosion. The principal erosional continued repetition of this process causes agents are running water, groundwater, glaciers, fatigue in the rocks and may lead to their wind and coastal waves. Each of the agents does disintegration. Many clay minerals swell erosion by distinctive processes and gives rise to and contract during wetting and drying and distinctive landforms. There are five common a repetition of this process results in cracking aspects of erosion by the above mentioned of overlying materials. Salts in pore spaces agents. undergo rapid and repeated hydration (1) The acquisition of rocks fragments. and help in rock fracturing. The volume changes in minerals due to hydration will (2) Wearing away of rocks fragments. also help in physical weathering through (3) The breaking down of the rock particles by exfoliation and granular disintegration. mutual wear while in transit. (d) Carbonation: Carbonation is the reaction (4) Transportation of the acquired rock debris. of carbonate and bicarbonate with minerals (5) Ultimately the deposition in the low lying and is a common process helping the areas. breaking down of feldspars and carbonate minerals. Carbon dioxide from the Mass Wasting atmosphere and soil air is absorbed by water, to form carbonic acid that acts as a Mass wasting is the movement of material weak acid. Calcium carbonates and down a slope under the influence of gravity. It magnesium carbonates are dissolved in is a transitional phenomenon between carbonic acid and are removed in a solution weathering and erosion. Mass Wasting is of without leaving any residue resulting in Various Types: Land-slide, Debris avalanche, Earth-flow, Mud-flow, and Sheet-flow etc. cave formation. (e) Hydrolysis: The mineral of the rocks and (a) Soil creep: In soil covered slope extremely water molecules react in such a way that new slow downslope movement of soil and over mineral compounds are formed. Silicate burden may be found. This process is called minerals are most affected by defrosts. as soil creep. (f) Chelation: Chelation is a complex organic (b) Talus cones: Steep rocks walls of gorges process by hydrocarbonwww.OnlineIAS.com molecules. and high mountains shed countless rock Chelation is form of Chemical weathering particles under the attack of physical by plants. weathering processes. These weathering processes are interrelated. (c) Earth Flows: In humid climate region, if Hydration, carbonation and oxidation go slope are steep, masses of water-saturated hand in hand and hasten the weathering soil due to over burden or weak bedrock may process. side down slope during a period of few III. Biological Weathering: This type of hours. weathering is performed by the tree roots, (d) Mud flow: Rapid flowage of mud stream animals and human beings. As the plant down a canyon floor and spreading out on roots grow, they wedge the rocks apart and plain at the foot of a mountain range is called cause the widening of joints and other as mud flow. fractures. Micro animals like earthworms, (e) Landslide: The downslope movement of ants, termites and other burrowing animals regolith of bed rock is called as landslide.

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GEOMORPHOLOGICAL LANDFORMS

central Europe, the Pennines, the Highland of Mountains Scotland, etc. These mountains were A mountain is defined as “a natural folded in very ancient times, and then elevation of the earth surface rising more or less subjected to denudation and uplift. Many abruptly from the surrounding level and faults were formed and the layers of the attaining an altitude which, relative to the rock were wrapped. Many mountains exist adjacent elevation, is impressive or notable”. as relicts due to erosion. Mountains can be classified on the basis of their structure or their origin. II. Block Mountains: They are originated by tensile forces leading to formation of rift A. Structural classification: valleys. They are also called horst I. Fold Mountains: These mountains have mountains e.g. black forest, Vosges, originated due to compressional tectonic Vindhya, Satpura, Sierra Nevada etc. When forces and have been thrown up to form the crust cracks due to tension or fold mountains e.g. Himalayas, Andes, Alps compression faulting takes place. A section etc. The folds consist of two inclined parts of the landform may subside or rise above the called limbs, the upfold is called anticline surrounding level giving rise to Rift valley and the downward portion is called or Graben and Block Mountains or Horst. The syncline. Block Mountains have a steep slope towards the rift valley but the slope on the other All young folded mountains have originated side is long and gentle. from geosynclines. Geosynclines are long narrow III. Dome Mountains: They are originated by and shallow water depressions characterized by magmatic intrusion and upwarping of sedimentation and the subsequent subsidence. crustal surface e.g. lava domes, Batholith The conversion of geosynclines into folded domes etc. mountains requires geologically long time with definite phases of mountain building process- IV Mountain of Accumulation: They are originated by accumulation of volcanic (b) Orogenesis: After horizontal compression material e.g. cinder cones, composite cones has completed its task, vertical uplift starts. etc. These are formed by the emission and This is the real stage of mountain building. deposition of lava and so they are also (c) Glyptogenesis: Inwww.OnlineIAS.com this phase the called volcanic mountains. The slope of the characteristic land forms are sculptured by mountains becomes steep and the height erosion. increases due to the development of the cones of various types like Cinder cones, On the basis of age the Fold Mountains can be Composite Cones, Acid lava cones, Basic grouped into: lava cones, etc. Some of the examples of (i) New or Young fold Mountains: Example: this type are Popocatepetl of Mexico, Mount The Alps, the Himalayas, the Circum-Pacific Rainier of Washington, Lessen Peak of oceanic Mountains, etc. The main features California, the Vesuvius of Italy, the of these mountains are the complex folding of Fujiyama in Japan, the Aconcagua in Chile the rocks, faulting, volcanic activities, and the etc. erosion caused by running water, ice, winds, V Circum Erosional or Relict Mountain: e.g. etc. Vindhyachal ranges, Aravallis, Satpura, (ii) Old Fold Mountains: Example: The Eastern and Western Ghats, Nilgiris, Caledonian and Hercynian mountains of Parasnath, Girnar, Rajmahal. These

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mountains have been subjected to 5. The sky line is irregular. weathering and erosion for a long time and B. The Maturity of Mountains: lowered down. They represent the old stage of mountain life cycle. 1. The rivers are mature and many water- B. Classification on the basis of Mountain gaps exist in the area. Building periods 2. The height of the mountains is not much. • Pre-Cambrian Mountains: Rocks of 3. The peaks are rounded, generally covered these mountains are older than the Cam- by thick vegetation. brian era, and are found in older stable blocks or old shields which are now 4. Landslides are uncommon and no metamorphosed. Some of those old earthquakes are experienced. shields are Laurentia, Fennoscandinevia 5. Slopes are not steep. Pebbles and rock (Europe), Angaraland (Asia), fragments are accumulated in the piedmont Gondwanaland (Asia), etc. area. • Caledonian Mountains: (320 m.yrs.): Mountains of Scandinavia, Scotland, N. C. The Old-Age of Mountains:

America, Aravallis, Mahadeo, Satpura 1. The rivers have attained old age. fall under this category. This mountain building process started at the end of 2. Monadnocks are found denuded and are a the Silurian period or at the beginning common sight. of the Devonian period. 3. The mountains are low. Peneplain • Hercynian Mountains: (240m.yrs.): condition seems imminent. These Mountains were formed during 4. The area is broad, low and leveled which Permian and Permo-Carboniferous pe- has wavy hills at some places. riod. They include Appalachian in N. America, Meseta in Spain, Vosges and Plateau Black Forest in Germany, Harz, Donetz area of Ural , Altai, Kinghan ,Tien Plateaus are extensive upland areas Shan, Alai, Nan-Shan, etc. Meseta characterized by flat and rough top surface and Mountains in Morocco; the High Atlas steep walls which rise above the neighbouring Mountains also represent this category. ground surface at least for 300 m. • Alpine Mountains (30m.yrs.): It started by the end of the Mesozoic era and con- On the basis of mode of formation the plateaus can be classified into: tinued upto the Tertiary period. These are the highest mountains of the world. 1. Plateaus Formed by Running Water: Many Being newer, the erosional forces could parts of the Deccan of India (Kaimur not erode them into a Peneplain like the Plateau, Rewa Plateau, Rohtas Plateau, Himalayas, the Alps, the Rockies, the Bhander Plateau), Brazilian Plateau. Andes, the Atlas, etc. www.OnlineIAS.com2. Plateaus formed by Glacial Erosion: Stages of Mountains Building: The life Plateau of Greenland and Antarctica, history of mountains can be divided into youth, Garhwal Plateau. maturity and old stage. Following are the 3. Plateaus formed by Glacial Deposition: characteristics of mountains in different stages:- Russian Plateau, Finland Plateau, Merg of Kashmir. A. The Youth Mountains: 4. Aeolian plateaus: Loess Plateau of China, 1. The rivers are youthful and the valleys are Potwar Plateau of Rawalpindi in Pakistan. deep and their flow is fast. 5. Plateaus formed by endogenic processes: 2. Landslide and volcanic activities are (a) Intermontane Plateaus: Tibetan Plateau, common. Bolivian Plateau, Peruvian Plateau, 3. The mountains are high. Columbian Plateau, Mexican Plateau. 4. The slopes are steep and the piedmont is (b) Piedmont Plateaus: Appalachian Pla- bare.

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teau, Patagonian Plateau, Colorado Pla- drainage is dendritic in nature. teau. (b) The Dissected Plains of Maturity: Such (c) Dome Plateaus: Ozark Massif (USA), plains are found in North Missouri, Chhotanagpur Plateau. Southern Iowa and Eastern Nebraska of (d) Lava Plateaus: Columbian Plateau, USA. Areas of gentle slope are very limited Mahabaleshwar Plateau. and plain areas are available more in the (e) Continental Plateau: Deccan plateau, valleys and the water divides are reduced Ranchi plateau, Shillong plateau, Colum- to small ridges. bia Plateau, Mexican Plateau etc. etc. (c) The Plains of Old Age: Peneplain and (f) Coastal Plateau: Coromandal coastal Panplains usually represent this stage of upland of India. plains. (g) Rejuvenated Plateau: Missouri Plateau (USA). Peneplain: Very few areas like Guinea plain (h) Mature Plateau: Ranchi Plateau, in the north-east S. America are fully developed Hazaribagh Plateau, Appalachian Pla- peneplains. The Appalachian had developed teau (USA). into peneplains in the ancient times but was later (i) Young Plateau: Idaho Plateau (USA), uplifted again. Here the high summits are of Colorado Plateau (USA), equal heights. Mahabaleshwar Plateau, Khandala up- Panplains: A plain formed of flood plains land (Maharashtra). joined by their own strength. It is a product of Plains lateral erosion by streams.

2. Glaciated Plains : When the ice sheet Plains can be defined as flat areas with low melted specially in N. America and W. height. They may be above or below sea level e.g. Eurasia , the area eroded by ice was coastal plains of Netherlands. exposed . Here the rivers have adjusted The plains may be classified as under: themselves before the extension of ice sheet. Lakes, swamps, waterfalls and rapids are 1. Formation of plain due to deposition of common. sediments over submerged coastlands e.g. 3. Aeolian Plains: Winds blow the sand and Coromandal coastal plains. starts the activities of deflection, abrasion, 2. River deposited plains e.g. north Indian etc. The plains produced by the wind plains actions are Reg, Serir and Hamada. 3. Piedmont alluvial plain e.g. Bhabar plain 4. Plains of Semi-arid Denudation : This 4. Flood plains e.g. Khadar and Bhangar type of plain includes the peneplains of plains USA and the pediplains of south-west of Africa. 5. Lava plains e.g. plains of New Zealand, Iceland etc. 5. Plains at Continental Edges: Theses have evolved at the sea coast by the action of 6. Glaciated plains e.g.www.OnlineIAS.com north west Eurasian waves and later uplifted. The flat plains plain. situated at the coast of Norway fall into A. Erosional Plains this category. 6. Karst Plains: They are found in limestone 1. Plains of Fluvial Erosion: The plains areas. The underground water removed the formed by river erosion have a lot of limestone layer by the process of solution. variation because of the stages of A large number of depressions are erosional development, the initial slope and produced in these plains e.g. the coastal the structure of basal rocks. plain of Adriatic Sea and the Karst plain (a) The Dissected Plains of the Youth: The of Florida (USA). Colorado, Kansas, Nebraska, east of the Rockies belong to this category of plains. B. Depositional Plains The broad water-divides, large valleys are the 1. Plains of Alluvial Deposition : The main characteristics of such plains. The

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deposition of the sediments takes place Denmark, The Gulf of Mexico in U.S.A., in three areas - the floor , the mouth and etc. the valley of the river where the slope suddenly decreases. The shape of such Lakes

depositional plain changes according to the Lakes may be defined as non-permanent method and place of deposition and forms features of static water on the land surface. The three types of plains. lakes can be classified as under: • Flood Plains: Here the river deposits its sediments by meandering through its 1. Fresh water lakes e.g. the great lakes of course. The flood plains of Mississippi, U.S.A. Ganga, Indus and Nile are good ex- 2. Saline lakes e.g. great salt lake of Utah, amples. Caspian sea, dead sea, lake van etc. • Deltaic Plains: When the river termi- 3. Fluvial lakes e.g. Wular lake, Marigot lake, nates in the sea or lake, the deltas are Mayeh lake formed due to deposition. The deltaic plains resemble flood plains but the ex- 4. Lakes formed by volcanic Activity: Crater istence of large number of distributaries and Caldera Lakes- Lake Oregon (USA), provides them with a distinction. Lakes Toba (Sumatra) Marshes and natural levees are common 5. Lakes formed by earth movements: here. The Deltaic plains of the Ganga, I. Tectonic Lakes: - Lake Titicaca (Andes), the Indus, the Nile and the Mississippi (highest Lake of world), Caspian Sea are famous. (Largest Lake of the world). • Piedmont Alluvial Plains: The piedmont II. Rift valley Lakes:- Tanganyika, Malawi, alluvial fans combine together and form Rudolf, Edward, Albert, Dead Sea (1256 a plain. Rough particles are found at ft below mean sea level the world’s the apex but the particles of debris get Lowest Lakes) finer as we move towards the periph- 6. Lakes formed by deposition: ery. 2. Plains of Glacial Deposition: These are I. Due to river deposits – Ox-bow Lakes

found in N. America and Europe, in areas II. Due to marine deposits – Lagoons, Delta which were affected by glacial action. The surface is slightly undulating and has low 7 Lakes formed by Erosion: and broad ridges and depressions. I. Karst Lakes – Lake Scutari (Yugoslavia) 3. Desert Plains of Wind Erosion: The Loess II. Wind – deflated Lakes (Salt Lakes & Pla- Plain of China was formed by the yas) windblown deposition of Gobi desert, 8. Lakes formed by Glaciations: situated west of it. Some other examples of I. Cirque Lakes of Tarns – Lake Red Tarn such plains are the Sahara of Africa, the (U.K.) Koum of Russianwww.OnlineIAS.com Turkistan, the north- II. Kettle Lakes – Orkney (Scotland) central Nebraska, etc. III. Rock-hollow Lakes – Lakes of Finland 4. Plains of Marine Deposition: They develop (the land of lakes) near the coast of shallow sea. Sand, IV. Lake due to Moraines – Lake alluvium, vegetation, etc. are deposited at Windermere (U.K.) the coastal areas of Netherlands, Germany, V. Lakes due to deposition of glacial drifts- North Ireland.

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VOLCANOES AND EARTHQUAKES

(b) Dormant volcano e.g. Vesuvius, Barren Volcano island volcano (Andaman) A volcano is a vent or opening usually (c) Extinct volcano e.g. where no indica- circular in form through which heated materials tion of future eruption is estimated. consisting of gases, water, liquid lava and 2. Classification on the basis of the mode fragments of rocks are ejected from the highly of eruption: heated interior to the surface of the earth. (A) Volcanic of central Eruption type- Eruption Magma is molten rock within the Earth’s crust. occurs through a central pipe and small When magma erupts through the earth’s opening are rapid and violent. Such surface it is called lava. Lava can be thick and volcanoes are very destructive and slow-moving or thin and fast-moving. Rock also disastrous. It is divided into 5 sub types as comes from volcanoes in other forms, including follow:- ash (finely powdered rock that looks like dark smoke coming from the volcano), cinders (bits (a) Hawaiian Types: Such Volcanoes erupt of fragmented lava), and pumice (light-weight quietly due to less viscous Laves and rock that is full of air bubbles and is formed in non-violent natures of gases. They emit explosive volcanic eruptions - this type of rock long glossy threads of red molten Lava can float on water). known as peel’s hair e.g. Hawaiian Is- land. Volcanic eruptions are closely associated with (b) Strombolian Type: The eruptions are several interconnected processes such as almost rhythmic or nearly continuous in nature but sometimes they are inter- (i) The gradual increase in temperature with rupted by long intervals. Ex- Stromboli increasing depth at a rate of 1°c per 32m volcano of Lipari island. due to heat generated by degeneration of (c) Vulcanian Type: Such volcanoes erupt radioactive elements inside the earth. with great force and intensity The Lava (ii) origin of magma because of lowering of is so viscous and pasty that these are melting point caused by reduction in quickly solidified e.g. Mt. Vulcano of pressure of overlying rocks due to fractures Lipari Island of Mediterranean Sea. caused by splitting of plates (d) Peleean Type: Most violent and most (iii) origin of gases andwww.OnlineIAS.com water vapour due to explosive type of volcanoes, named as heating of water Nuee Ardente, meaning thus by glow- ing cloud e.g. Pelee volcano of (iv) ascent of magma due to pressure from Martinique Island in the Caribbean Sea, gases and vapour Krakatau volcano between Java and (v) Occurrence of volcanic eruption. These Sumatra in Sunda strait. eruptions are closely associated with plate (e) Visuvian type: Extremely violent and boundaries. enormous volume of gases and ashes forms which clouds like cauliflower. This Volcanoes are classified under different is also called Plinian type. schemes: (B) Fissure eruption or quiet eruption type 1. Classification on the basis of periodicity e.g. Lava flow or flood, mud flow and of eruptions: fumaroles. Large quantities of lava quietly (a) Active volcano e.g. Etna, Stromboli, well up from fissure and spread out over Pinatubo etc. the surrounding countryside. Successive lava flows results in the growth of a lava platform which may be extensive to be

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called a plateau like “Deccan” “Columbia becomes dormant after a while and a new snake plateau”, Drakensberg mountains”, volcano is then formed as the plate shifts over the “Victoria and Kimberley” districts of hotspot. The Hawaiian Islands are thought to be Australia, “ Java island”. formed in such a manner, as well as the Snake River Plain, with the Yellowstone Caldera of the Plate tectonics and Volcanoes North American plate currently above the hot spot. Another example is India’s Deccan A. Divergent plate boundaries plateau which is the result of lava outflow from the Reunion hotspot. At the mid-oceanic ridges, two tectonic plates diverge from one another. New oceanic Topography produced by volcanoes: crust is being formed by hot molten rock slowly cooling and solidifying. The crust is very thin at (i) Cinder or ash cone: They are of low height mid-oceanic ridges due to the pull of the tectonic and are formed of volcanic dust, ashes and plates. The release of pressure leads to partial pyroclastic matter. Its formation takes place melting of the mantle causing volcanism and due to accumulation of finer particles creating new oceanic crust. Most divergent plate around the volcanoes vent. boundaries are at the bottom of the oceans, (ii) Shield volcanoes: So named for their therefore most volcanic activity is submarine, broad, shield-like profiles, are formed by forming new seafloor. Black smokers or deep the eruption of low-viscosity lava that can sea vents are an example of this kind of volcanic flow a great distance from a vent, but not activity. Where the mid-oceanic ridge is above generally explode catastrophically. Since sea-level, volcanic islands are formed, for low-viscosity magma is typically low in example, Iceland. silica, shield volcanoes are more common in oceanic settings. The Hawaiian volcanic B. Convergent plate boundaries chain is a series of shield cones, and they are common in Iceland as well. Subduction zones are places where two plates, usually an oceanic plate and a continental (iii) Composite cones: They are formed due to plate, collide. In this case, the oceanic plate the accumulation of different layers of subducts or submerges under the continental various volcanic materials. plate forming a deep ocean trench just offshore. (iv) Parasite cones: When lava comes out of Water released from the subducting plate lowers the minor pipes coming out of the main the melting temperature of the overlying mantle central pipe, parasite cones are formed. wedge, creating magma. This magma tends to be (v) Basic lava cone: It has less quantity of silica very viscous due to its high silica content so that in its lava. it often does not reach the surface and cools at (vi) Acidic lava cone: It has more silica in its depth. When it does reach the surface, a lava. volcano is formed. Typical examples for this kind of volcano are Mount Etna and the volcanoes (vii)Lava domes: These are formed due to in the Pacific Ring of Fire.www.OnlineIAS.com accumulation of solidified lavas around the volcanic vents. C. Hotspots (viii)Lava plugs: They are formed due to

plugging of volcanic pipes and vents when Hotspots are not usually located on the volcano becomes extinct. edges of tectonic plates, above mantle plumes, where the convection of the Earth’s mantle (ix) Craters: The depression formed at the creates a column of hot material that rises until mouth of a volcanic vent is called a crater. it reaches the crust, which tends to be thinner When it is filled with water, it becomes a than in other areas of the Earth. The ‘crater lake’ e.g. Lake Lonar in temperature of the plume causes the crust to melt Maharashtra. and form pipes, which can vent magma. Because (x) Calderas: Generally enlarged form of the tectonic plates move whereas the mantle craters is called caldera. It is formed due to plume remains in the same place, each volcano

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subsidence of a crater. or lines of weakness marked by intense folding and faulting. (xi) Geysers: They are intermittent hot springs that from time to time spout steam and hot Earthquake water from their craters. (xii)Fumaroles: It is a vent through which there An earthquake is a vibration or oscillation is emission of gases and water vapour. of the surface of the earth caused by a transient (xiii)Cryptodomes: These are formed when disturbance of the elastic or gravitational viscous lava forces its way up and causes equilibrium of the rocks at or beneath the surface. a bulge. The 1980 eruption of Mount St. The magnitude or intensity of energy released by Helens was an example. Lava under great an earthquake is measured by the richter scale. pressure forced a bulge in the mountain, The place of the origin of an earthquake is called which was unstable and slid down the focus which is hidden inside the earth. The place north side. on the ground surface which is perpendicular (xiv)A supervolcano is a large volcano that to the buried focus is called ‘epicentre’. Seismic usually has a large caldera and can waves are recorded by an instrument called potentially produce devastation on an ‘seismograph’. Isoseismal lines join places which enormous, sometimes continental, scale. experience the earthquake at the same time. Such eruptions can cause severe cooling of global temperatures for many years Causes of Earthquakes: afterwards because of the huge volumes If seen broadly we can say that earthquakes of sulphur and ash erupted. They are the most dangerous type of volcano. Examples are caused due to two major reasons. The first include Yellowstone Caldera in reason is the eruption of volcanoes, which are Yellowstone National Park and Valles sudden. Volcanoes are seats of inner disturbance Caldera in New Mexico (both western and can affect the plates which are the second United States), Lake Taupo in New cause of earthquakes. Earthquakes are caused Zealand, Lake Toba in Sumatra and due to disturbance in the movement of plates, Ngorogoro Crater in Tanzania. which again can be caused due to various Supervolcanoes are hard to identify reasons like under-crust waves or cracks in the centuries later, given the enormous areas plates. they cover. Large igneous provinces are also considered supervolcanoes because of A. Plate Tectonic Theory the vast amount of basalt lava erupted, but are non-explosive. The outer layer of the earth is divided into many sections known as plates, which are Distribution of volcanoes floating on the molten magma beneath the

Volcanoes are unevenly distributed over the earth’s crust. Now the movement of these plates earth and vast areas have no active volcanoes at is determined by the convection current in the all. There are no volcanoes in Australia. In Asia, molten magma. Therefore after intervals there they are largely concentratewww.OnlineIAS.comd in circum-pacific are plates that get submerged in the molten region and Africa has a few of them. Thus, the magma and there are plates that rise upwards pacific belt is truly known as the “ring of fire” and at times even new crust is formed from the because of the largest number of active volcanoes molten magma which in turn forms a new plate along the coasts of America and Asia around until it connects itself with the already existing this region. Iceland, Sicily and Japan are the ones. At times these plates and can be pushed up biggest volcanic islands in the world. Most of the to form mountains and hills and the volcanoes in the world occur along linear belts movement is so slow that it is really hard to comprehend that there is any movement at all. The movement and the results come out to be visible suddenly. Now these plates are the bases on which the continents stand and when these plates move the continents also move. Most of the earthquakes occur on the edges of the plates

www.OnlineIAS.com N. Kalyana Chakravarthy 35 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] where a plate is under, on or across another endogenetic forces: plate. This movement disrupts the balance and I. Volcanic earthquake: they are caused position of all plates, which leads to tremors, due to volcanic eruptions. E.g. Earth- which are called earthquakes. quakes caused by explosion of Krakatau volcano in 1883 and Etna volcano in B. Volcanic Eruptions 1968. II.Tectonic earthquake: they are caused When volcanoes erupt it is because the due to dislocation of rock blocks during molten magma under the crust of the earth is faulting e.g. 1906 earthquake of Califor- under enormous pressure and to release that nia and 1923 earthquake of Sangami pressure it looks for an opening and exerts bay, Japan etc. pressure on the earth’s crust and the plate in turn. III. Isostatic earthquake: they are triggered A place, which is the seat of an active volcano, due to sudden disturbance in the isos- is often prone to earthquakes as well. tatic balance at regional scale due to Earthquakes are also caused after a volcanic imbalance in geological processes e.g. eruption since the eruption also leads to a near active mountain building zones. disturbance in the position of plates, which either IV.Plutonic earthquakes: these are deep move further or resettle and can result into severe focus earthquakes generally located be- or light tremors. tween 240 and 670 km deep. The excessive exploitation of earth’s 2. Artificial earthquakes: They are caused resources for our own benefits like building dams due to man-made activities like pumping to store large volumes of water (earthquake at water and mineral oil underground, Koyna Nagar Township) and blasting rocks and blasting of rocks, nuclear explosion, storage mountains to build bridges and roads is also the of huge volume of water in reservoirs etc. reason behind such natural disruptions. Examples of earthquake due to construction of huge dams include Koyna earthquake Effects of 1967 and Hoover dam earthquake of

1936. (1) Landslides and damming of the rivers in highland regions.

(2) Causes depression forming lakes. May cause faults, thrusts, folds, etc

(3) Formation of cracks or fissures in the epicenter region and some- times water, mud, gas are ejected from it.

(4) Causes the raising or lowering of parts of the sea floor e.g. “Sangami bay” in 1923.

This causes “tsunamis” or tidal waves. (5) May change surfacewww.OnlineIAS.com drainage & underground circulation of water like the Distribution of Earthquakes sudden disappearance of springs in some About 68% of all the earthquakes are places. observed in the vast region of the pacific ocean (6) Rising and lowering of crustal regions for known as the “ring of fire” and is closely linked example in Alaska in 1899-16 m upliftment. with the region of crustal dislocations and (7) Devastation of cities, fires, diseases, etc. volcanic eruptions. Chile, California, Alaska, Japan, Philippines, New Zealand constitute the Classification of earthquakes ring of fire.

Earthquakes are classified on the basis of Around 21% of the earthquakes occur in the causative factors: mid-word mountain belt extending parallel to the equator from Mexico across Atlantic Ocean, 1. Natural earthquakes: They are caused by the Mediterranean Sea from Alpine-Caucasus ranges to the Caspian, Himalayan Mountains

www.OnlineIAS.com N. Kalyana Chakravarthy 36 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] and the adjoining belts: the earthquakes in India 4. Earth’s magnetic north and South Pole are are at present mainly confined to the Himalayan located on Prince of Wales Island in regions and its foot hills. They are also felt in the Canada and South Victoria island in Ganga valley. Antarctica, respectively. 5. “Homoseismal line” is the line joining places Points to Remember that experience earthquake at the same

1. The largest crater known to have formed time. by a meteorite is Coon Butte or Barringer 6. The only active volcano in India is Barren crater in USA. Lonar lake of Maharashtra Island in Andaman-Nicobar islands. is the largest meteoric Crater Lake in India. 7. Seismic waves that cause maximum 2. Earth’s rotational velocity at equator is 1690 destruction is ‘L’ or long waves. km/hr. 8. Magnitude of earthquake is measured on 3. Elastic rebound theory explains Richter scale. anthropogenic earthquake.

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EROSIONAL AND DEPOSITIONAL LANDFORMS

C. Meanders Fluvial Landforms

Rivers are a sizable stream of freshwater River meanders refers to the bends of flowing through a natural channel in the land. longitudinal cources of the rivers. The shape of Rivers are among the most powerful natural the meander is usually semi circular. It is forces in shaping the earth’s surface. In draining governed by lithological characteristics, the land of surplus water, rivers wear down topographic characteristics, annual mountains, plateaus, and other high landforms. precipitation, cycle of erosion etc. In a never-ending process, eroded material is • Depositional Landforms carried by rivers. Some is deposited to form A. Alluvial Fans floodplains in the valleys, some forms deltas at the rivers’ mouths, and some is deposited in the Alluvial fans are fan-shaped deposits of sea. water-transported material (alluvium). They • Erosional Landforms typically form at the base of topographic features where there is a marked break in slope. A. Valleys Consequently, alluvial fans tend to be coarse-

Valleys start as small and narrow rills; the grained, especially at their mouths. At their rills will gradually develop into long and wide edges, however, they can be relatively fine- grained. gullies; the gullies will further deepen, widen and lengthen to give rise to valleys. Depending upon dimensions and shape, many types of valleys like V-shaped valley, gorge, canyon, etc. forms.

A gorge is a deep valley with very steep to straight sides and a canyon is characterised by steep step-like side slopes and may be as deep as a gorge. A gorge is almost equal in width at its top as well as its bottom. In contrast, a canyon is wider at its top than at its bottom. In fact, a canyon is a variant owww.OnlineIAS.comf gorge. Valley types depend upon the type and structure of rocks in B. Delta which they form. For example, canyons commonly form in horizontal bedded Deltas are built from primarily river-borne sedimentary rocks and gorges form in hard sediment. It forms when the amount of sediment rocks. delivered at the mouth of a river exceeds the amount removed by waves and tidal currents B. Potholes and Plunge Pools

Over the rocky beds of hill-streams more or less circular depressions called potholes form because of stream erosion aided by the abrasion of rock fragments. Once a small and shallow depression forms, pebbles and boulders get collected in those depressions and get rotated by flowing water and consequently the depressions grow in dimensions. Such large and deep holes at the base of waterfalls are called plunge pools. www.OnlineIAS.com N. Kalyana Chakravarthy 38 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected]

C. Natural leeves the bottom of a sinkhole forms the roof of a void or cave underground, it might collapse leaving The narrow belt of ridges of low height built a large hole opening into a cave or a void below by the deposition of sediments by the spill water (collapse sinks). Quite often, sinkholes are of the stream on the either bank is called natural covered up with soil mantle and appear as leeve. shallow water pools. The term doline is sometimes used to refer the collapse sinks. When Karst Topography sink holes and dolines join together because of slumping of materials along their margins or due Karst is a distinctive topography in which to roof collapse of caves, long, narrow to wide the landscape is largely shaped by the dissolving trenches called valley sinks or Uvalas form. action of water on carbonate bedrock (usually Gradually, most of the surface of the limestone limestone, dolomite, or marble). is eaten away by these pits and trenches, leaving This geological process, occurring over many it extremely irregular with a maze of points, thousands of years, results in unusual surface grooves and ridges or lapies. and subsurface features ranging from sinkholes, vertical shafts, disappearing streams, and springs, to complex underground drainage systems and caves.

The process of karst formation involves what is referred to as “the carbon dioxide cascade.” As rain falls through the atmosphere, it picks up CO2 which dissolves in the droplets.

Once the rain hits the ground, it percolates through the soil and picks up more CO2 to form a weak solution of carbonic acid:

H2O+CO2=H2CO3.

The infiltrating water naturally exploits any cracks or crevices in the rock. Over long periods, B. Caves with a continuous supply of CO - enriched 2 In areas where there are alternating beds of water, carbonate bedrock begins to dissolve. rocks (shales, sandstones, quartzites) with Openings in the bedrock increase in size and limestones or dolomites in between or in areas an underground drainage system begins to where limestones are dense, massive and develop, allowing more water to pass, further occurring as thick beds, cave formation is accelerating the formation of karst. Eventually prominent. Water percolates down either this leads to the development of subsurface caves. through the materials or through cracks and • Erosional Landforms joints and moves horizontally along bedding www.OnlineIAS.complanes. It is along these bedding planes that the A. Pools, Sinkholes, Lapies and Limestone limestone dissolves and long and narrow to wide Pavements gaps called caves result. There can be a maze of caves at different elevations depending upon the Small to medium sized round to sub- limestone beds and intervening rocks. Caves rounded shallow depressions called swallow normally have an opening through which cave holes form on the surface of limestones through streams are discharged. Caves having openings at solution. Sinkholes are very common in both the ends are called tunnels. limestone/karst areas. A sinkhole is an opening more or less circular at the top and funnel- • Depositional Landforms shapped towards the bottom with sizes varying Many depositional forms develop within the in area from a few sq. m to a hectare and with limestone caves. The chief chemical in limestone depth from a less than half a metre to thirty is calcium carbonate which is easily soluble in metres or more. Some of these form solely carbonated water (carbon dioxide absorbed through solution action (solution sinks) and rainwater). This calcium carbonate is deposited others might startas solution forms first and if

www.OnlineIAS.com N. Kalyana Chakravarthy 39 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] when the water carrying it in solution evaporates erosion forms a broad erosional platform called or loses its carbon dioxide as it trickles over rough a wave-cut bench or wave-cut platform. After the rock surfaces. constant grinding and battering, eroded material is transported to adjacent bays to A. Stalactites, Stalagmites and Pillars become beaches or seaward coming to rest as a wave-built terrace. If tectonic forces raise the Stalactites hang as icicles of different bench above the water level a marine terrace diameters. Normally they are broad at their bases forms. Some shorelines have several marine and taper towards the free ends showing up in terraces creating during various episodes of a variety of forms. Stalagmites rise up from the uplift. floor of the caves. In fact, stalagmites form due to dripping water from the surface or through the thin pipe, of the stalactite, immediately below it

Stalagmites may take the shape of a column, a disc, with either a smooth, rounded bulging end or a miniature crater like depression. The stalagmite and stalactites eventually fuse to give rise to columns and pillars of different diameters.

Coastal Geomorphology • Depositional Landforms

Coastal Geomorphology encompasses the A. Beaches and Dunes study of coastal processes and the evolution of landforms. Beaches are characteristic of shorelines that are dominated by deposition, but may occur as The formation and development of cliffs, patches along even the rugged shores. Most of beaches, salt marshes, reefs and other coastal the sediment making up the beaches comes from landforms reflect the pressures and forces acting land carried by the streams and rivers or from upon a coastline, both natural and manmade. wave erosion. Beaches are temporary features. • Erosional Coastal Landforms The sandy beach which appears so permanent may be reduced to a very narrow strip of coarse Some of the most spectacular scenery is pebbles in some other season. found along coastlines and produced by the effects of wave erosion. Wave erosion undercuts Most of the beaches are made up of sand steep shorelines creating coastal cliffs. sized materials. Beaches called shingle beaches contain excessively small pebbles and even A. Sea cliff is a vertical precipice created cobbles. by waves crashing directly on a steeply inclined slope. Hydraulic action, abrasion, and chemical B. Bars, Barriers and Spits solution all work to cut www.OnlineIAS.coma notch at the high water level near the base of the cliff. Constant A ridge of sand and shingle formed in the sea undercutting and erosion causes the cliffs to in the off-shore zone (from the position of low retreat landward. tide waterline to seaward) lying

B. Sea caves form along lines of weakness approximately parallel to the coast is called an off-shore bar. in cohesive but well-jointed bedrock. Sea caves are prominent headlands where wave refraction An off-shore bar which is exposed due to attacks the shore. further addition of sand is termed a barrier bar.

A sea arch forms when sea caves merge The off-shore bars and barriers commonly form across the mouth of a river or at the entrance of from opposite sides of a headland. If the arch collapses, a pillar of rock remains behind as a sea a bay. Sometimes such barrier bars get keyed up stack. to one end of the bay when they are called spits (Figure 7.15). Spits may also develop attached Seaward of the retreating cliffs, wave

www.OnlineIAS.com N. Kalyana Chakravarthy 40 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] to headlands/hills. The barriers, bars and spits glacier disappears. Such lakes are called cirque at the mouth of the bay gradually extend leaving or tarn lakes. There can be two or more cirques only a small opening of the bay into the sea and one leading into another down below in a the bay will eventually develop into a lagoon. stepped sequence. The lagoons get filled up gradually by sediment coming from the land or from the beach itself B. Horns and Serrated Ridges

(aided by wind) and a broad and wide coastal Horns form through head ward erosion of plain may develop replacing a lagoon. the cirque walls. If three or more radiating glaciers cut headward until their cirques meet, high, sharp pointed and steep sided peaks called

horns form. The divides between cirque side walls or head walls get narrow because of progressive erosion and turn into serrated or saw- toothed ridges sometimes referred to as arêtes

with very sharp crest and a zig-zag outline.

C. Glacial stairways

The advancing ice of glaciers carves out giant

stairways through the process of abrasion and plucking of step faults coming across the path of moving glaciers

• Deposional Landforms

A. Moraines Glaciated Topography

Glaciers have played an important role in A valley glacier carries a large amount of the shaping of landscapes in the middle and high rock waste called moraine. The moraine forming latitudes and in alpine environments. Their along the sides of a glacier is called lateral ability to erode soil and rock, transport moraine; that along the front of a glacier is called sediment, and deposit sediment is terminal moraine; that at the bottom of a glacier is extraordinary. During the last glacial period the ground moraine. When two glaciers join more than 50 million square kilometers of land together, their inner lateral moraines coalesce to surface were geomorphically influenced by the give a medial moraine. Terminal moraine presence of glaciers. material is carried down-valley by the melt waters issuing from the glacier’s snout (front) • Erosional Landforms and is deposited as a layer called an outwash Glacial erosion consists of two processes: (i) plain. One of the most conspicuous features of plucking or the tearing away of blocks of rock lowlands which have been glaciated by ice sheets which have become frozewww.OnlineIAS.comn into the base and is the widespread morainic deposits. Because of sides of a glacier, and (ii) abrasion or the wearing the numerous boulders in the clay these are called away of rocks beneath a glacier by the scouring boulder clay deposits. action of the rocks embedded in the glacier. B. Drumlins A. Cirque The swarms of rounded hummocks resulting Cirques are the most common of landforms from the deposition of glacial till are called in glaciated mountains. The cirques quite often drumlins. They look like inverted boat or spoon. are found at the heads of glacial valleys. The accumulated ice cuts these cirques while moving C. Eskers down the mountain tops. They are deep, long and wide troughs or basins with very steep When glaciers melt in summer, the water concave to vertically dropping high walls at its flows on the surface of the ice or seeps down head as well as sides. A lake of water can be seen along the margins or even moves through holes quite often within the cirques after the

www.OnlineIAS.com N. Kalyana Chakravarthy 41 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] in the ice. These waters accumulate beneath the of meltwater, and deposits on the outwash plain, glacier and flow like streams in a channel at the terminus of the glacier. The outwash, the beneath the ice. Such streams flow over the sediment transported and deposited by the melt ground (not in a valley cut in the ground) with ice water and that makes up the fan, is usually poorly forming its banks. Very coarse materials like sorted due to the short distance traveled before boulders and blocks along with some minor being deposited. fractions of rock debris carried into this stream settle in the valley of ice beneath the glacier and after the ice melts can be found as a sinuous ridge called esker.

D. Outwash fan

An outwash fan is a fan-shaped body of sediments deposited by braided streams from a melting glacier. Sediment locked within the ice of the glacier, gets transported by the streams

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DRAINAGE SYSTEM & PATTERNS

The origin and evolution of any drainage example, Indus, Sutlej, Alaknanda and system in a particular region are determined and Brahmaputra are antecedent rivers as controlled by two factors- (a) Nature of original they originated before the upliftment of surface and slope (b) Geological structure. Himalayan ranges. (b) Superimposed Drainage: It is formed Streams or drainage systems are divided in when the nature and characteristics of two broad categories- the valley and the flow direction of a consequent stream, developed on the I. Sequent Drainage System upper geological formation and struc- (a) Consequent Stream: The upland forms ture, are superimposed on the lower the catchment area of rivers, where pre- geological formation of entirely differ- cipitation is heaviest and where there is ent characteristics. For example the river a slope down which the run off can Subarnarekha is superimposed on flow. The initial stream that exists as a Dalma Hills of Chhotanagpur Plateau of Jharkhand. consequence of the slope is called the consequent stream. Most of the streams, Drainage Patterns draining the coastal plains of India are of this type. (1) Dendritic Drainage: A drainage pattern (b) Subsequent Stream: When the master consisting of a single main stream with consequent stream is joined by its tribu- tributaries, resembling the branches of a tary at right angles, it is called subse- tree. This pattern develops perfectly where quent stream. For example, the river Son, the underlying rocks are of a uniform type a tributary of the Ganga is a subsequent and the structures are simple. stream. (2) Trellis Drainage: It is a rectangular (c) Obsequent Streams: The stream which pattern of river channels. It may develop flows following the direction of the slope where a slope is crossed at right angles by the opposite to master consequent stream. strike of alternating hard and soft rock strata. For example the Mahabharata Range of Long streams develop along the soft rock Lesser Himalayas has originated several strata and the short streams follow the streams from its northern slope which slope. join the subsequenwww.OnlineIAS.comt stream from the di- rection opposite to the consequent stream (3) Radial Drainage: Here the streams radiate e.g. Sun Kosi runs west to east as from a central peak or upland mass in all obsequent stream and the master conse- directions. Dome structures commonly quent streams like Ganga and Yamuna develop radial drainage as in the English flow in the opposite direction. Lake District of England. The entire (d) Resequent Streams: Such streams fol- drainage network of Sri Lanka, Hazaribagh low the direction of master consequent Plateau, Panchet Hills and Maikal Range stream and meet the subsequent streams are of such type. at right angles. (4) Rectangular Drainage: A pattern of II. Insequent Drainage System: The streams drainage consisting of two main directions which do not follow the regional slopes and of flow at right angles to one another. This drain across the geological structures are pattern is common where the streams called insequent or inconsequent streams. follow the fault lines. (a) Antecedent Drainage: The stream (5) Annular Drainage: Here streams follow which originated before the upliftment roughly in circular pattern. Such patterns of the surface on which they flow. For www.OnlineIAS.com N. Kalyana Chakravarthy 43 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected]

are usually produced on domed structures (8) Centripetal Drainage: When the streams where the rivers follow the outcrops of converge at a point, which is generally a weaker beds of rock in an alternating band depression or a basin they form centripetal of hard and soft beds. or inland drainage pattern. (6) Parallel Drainage: A pattern in which the (9) Herringbone Drainage: When the main streams and tributaries follow consequent streams are developed in the virtually parallel courses. This develops longitudinal parallel valley while the where there is a strong structural control tributaries, after originating from the hill in one direction or where strata are gently slopes of the bordering parallel ridges, join dipping. the longitudinal consequents almost at right angle, it is known as herringbone pattern (7) Barbed Drainage: In this pattern the or rib pattern. Jhelum River in the Vale of tributaries flow in opposite direction to their Kashmir receives many tributaries from master streams. The tributaries join their both the sides, following the rib pattern. master streams in a hook-shaped bend. Such pattern is generally developed due to river capture.

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ATMOSPHERE

Composition of Atmosphere Some of the gases behave like permanent atmospheric components as they remain in fix The atmosphere, a mixture of many gases, proportion of the total gas volume. Two gases, contains huge amount of solid and liquid nitrogen and oxygen constitute about 99% of the particles, collectively known as “aerosols”. Pure clean dry air. The deep layer through which the dry air consists mainly of Nitrogen (78%), gaseous composition of the atmosphere is Oxygen (21%), Argon (0.93%), Carbon dioxide generally homogeneous is called the (0.03%), Hydrogen, Helium and Ozone. Besides, “homosphere”. At higher altitude, the chemical water vapour, dust particles, smoke, salts are also constituents of air changes considerably and this present in air in varying quantities. As a result, layer is known as “heterosphere”. the composition of air is never constant and varies from time to time and place to place.

Data on Composition of Atmosphere

Gases Volume Height Characteristics and Functions Nitrogen 78.084% upto 100 km Not very active chemically, dilutant for oxygen, regulates combustion, Enters protein molecules via Soil planets Oxygen 20.946% upto 100 km chemically active combines readily with other elements, Released by plants in

photosynthesis, taken up by plants and animals in respiration. Argon 0.934% — Chemically inactive, Present in tiny portion Carbon-Dioxide 0.039% upto 50 km absorbs heat radiation from the earth in the atmosphere Neon 0.001818%www.OnlineIAS.com —- —- Helium 0.000524% — —- Methane 0.000179% — —-

Krypton 0.000114% — — Hydrogen 0.000055% — —- Nitrous Oxide 0.00003% — —- Carbon Monoxide 0.00001% — —-

Xenon 9 × 10"6% 30 to 50 km —- Ozone 7 × 10"6% 20 to 45 km Absorbs Ultra violet rays of Sun Nitrogen Dioxide 2 × 10"6% — —-

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Water vapour 0.40% over upto 8km Recycles in Evaporation –

Condensation

Full atmosphere Typically 1%-4% at surface Dust particles — Lower layers Gives the colour to sky (Blue) by

Scattering, decides the intensity of sunrays, acts as hygroscopic nuclei

Stratosphere: The region above the Structure of the Atmosphere tropopause extending up to 50 km above the The atmosphere consists of almost concentric earth is known as Stratosphere. Temperature layers of air with varying density and ceases to fall with the increase in height at this temperature. Density is highest on the earth’s level. The temperature at tropopause is about - surface and goes on decreasing upwards. 80°C over the equator and about - 45°C over the poles. The atmosphere can be divided into following layers: In the lower part of the stratosphere i.e. upto height of 20 km, temperature remains A. Troposphere: constant. Afterwards it gradually increases upto a height of 50 km because of the presence of The lowest layer of the atmosphere extending ozone layer. Clouds are almost absent and there to an average altitude of 10 km, varying between is little dust or water vapour. The air movements 18 km above the equator and 8 km above poles. are almost horizontal. The Stratospheric layer It is a region of clouds, water vapour and provides ideal conditions for flying large weather. Troposphere literally means the region aeroplanes. Cirrus clouds, called the “mother of of mixing. It contains about 75 percent of the pearl clouds”, occasionally form in the lower total mass of the atmosphere and practically all stratosphere. Above the tropopause no visible the moisture and dust particles. weather phenomena ever occur. The upper

boundary of the stratosphere is called Temperatur e decreases at the rate of 6°C per km of height above Sea level. The temperature “Stratopause”. at the end of the troposphere is around -80°C. B. Mesosphere: The boundar y line separatinwww.OnlineIAS.comg troposphere from stratosphere is known as Tropopause. It exists over the stratosphere extending upto

a height of about 80 km above the earth. Temperature sharply decreases with height and reaches the lowest level of -100°C at the top. Bulk of the meteors is destroyed in this region. Because of the preponderance of chemical processes this sphere is sometimes called the ‘Chemosphere’.

C. Ionosphere:

IAS It is located between 80 and 400 km. It is an electrically charged layer. Radio waves transmitted from the earth are reflected back by this layer. Temperature again starts increasing

www.OnlineIAS.com N. Kalyana Chakravarthy 46 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] with the height because of radiation from the farther from the sun and this position is Sun. At this level, the ionization of atmosphere called ‘aphelion’. Hence the amount of begins to occur. This layer was first of all incoming solar radiation is about 7 percent discovered by Kennelly and Heaviside. more in January. 2. Angle of Incidence: The oblique rays have Layers of Ionosphere: to travel longer distance through the

(i) D-Layer: It is the lowest layer of atmosphere before they strike the surface Ionosphere (60 km to 90 km). It reflects of the earth and large amount of energy is low-frequency radio waves but absorbs lost by various processes of reflection, medium and high frequency waves. It absorption, scattering, etc. At mid-day the disappears as soon as the sun sets. intensity of insolation is maximum. In winter and high latitudes the insolation (ii) E-Layer: It extends from 90 km to 120 km received is small. and called as “Kennelly-Heaviside layer”. It reflects the medium and high frequency 3. Duration of Sunshine: The most important radio waves. This layer also does not exist causes for the variation in the amount of at night. solar energy reaching the earth are the seasonal changes in the angle at which the (iii)F-Layer: The F layer, also known as the sun’s rays strike the surface and the length Appleton layer extends from about 200 of the day. km to more than 500 km above the surface of Earth. This layer is important in long Summer Solstice: 21st June Winter distance radio communication. It reflects Solstice: 22nd December Autumnal the medium and high frequency radio Equinox: 23rd September Spring waves. Equinox: 21st March. (iv) G-Layer: This is the uppermost part of Ionosphere. Because of the interaction of 4. Solar Constant: When the sun-spots appear ultraviolet photons with nitrogen atoms, in larger number, the intensity of the solar free electrons are produced in this layer. radiation received is increased. The number of sunspot changes on a regular basis in a D. Exosphere/Thermosphere: cycle of 11 years.

It is the uppermost layer of the atmosphere 5. Transparency of Atmosphere: Reflection extending beyond the ionosphere above a height from dust, salt, smoke particles, etc returns of 400 kilometres. This layer is extremely rarified short wave radiation to space. Similarly and gradually merges with the outer space. cloud tops deplete the amount of insolation. Hydrogen and helium gases dominate this Transparency of the atmosphere is closely region. Here the temperature may reach a high related to the latitudes. In the higher value of about 5568°C. latitudes the sun’s ray are more oblique. In winter when the altitude of the sun is Insolation/ Solarwww.OnlineIAS.com Radiation relatively lower, there is greater loss of incoming solar radiation than in summer. Incoming solar radiation is known as Isolation and it is received in the form of short Heat Budget waves. The earth’s surface receives the radiant energy at the rate of 2 calories per sq. cm. per The average temperature of the earth minute. remains rather constant. It has been possible because of the balance between the amount of Factors effecting the distribution of Insolation: incoming solar radiation and the amount of terrestrial radiation returned to space. This 1. Distance between Earth & Sun: The balance of incoming and outgoing radiation has average distance between these two bodies been termed as the earth’s heat budget. is about 149 million km. On January 3 the earth comes closer to the sun, called Let us assume that the total heat received at “perihelion”. On July 4, the earth is little the top of the atmosphere is 100 units. About 35

www.OnlineIAS.com N. Kalyana Chakravarthy 47 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] units are reflected back to space even before its energy supply from the earth and not reaching the earth’s surface. Of these, 27 units are directly from the sun. reflected back from the top of the clouds and 4. Convection & Advection: Heat gained by 2 units from the snow and ice-covered areas of the the layers of air at or near the earth’s surface earth. The reflected amount of radiation is called from radiation or conduction is transferred the Albedo of Earth. to the upper atmospheric layers by the process of convection. Whereas the term The remaining 65 units are absorbed, 14 convection is used for vertical motion in units within the atmosphere and 51 units by the the atmosphere, the term advection is used earth’s surface. The earth radiates back 51 units in for horizontal transport of heat. Advection the form of terrestrial radiation. Of these, 17 units is responsible for slow heat transfer from are radiated to space directly and the the equatorial to the polar regions. “Loo” remaining 34 units are absorbed by the is the example of advection. atmosphere - 6 units absorbed directly by the atmosphere, 9 units through convection and 5. Latent Heat of Condensation: Half of the turbulence and 19 units through latent heat of insolation received at the ocean surface is condensation. About 48 units absorbed by the consumed in the evaporation of surface atmosphere (14 units from insolation and 34 water. When the water vapour is units from terrestrial radiation) and also radiated condensed, the latent heat is again released back into the space. Thus the total radiation into the atmosphere and is used in heating returning from the earth and the atmosphere it. respectively is 17 + 48 = 65 units which balance 6. Expansion and Compression of Air: the total of 65 units received from the sun. Hence Whenever air moves upward it passes the heat balance of the earth is always through region of successively lower maintained. pressure and whenever descends the vice- versa. Rising air expands and cools Mechanism of Heat Transfer adiabatically. The descending air is

compressed and heated. Thus the There are certain processes which play temperature changes brought about in the significant role in the transfer of energy from the air aloft simply due to changes in the air earth surface to its atmosphere. The atmosphere pressure are very important in the heating is heated and cooled by the following processes: or cooling of the atmosphere. 1. Absorption by Atmosphere: About 14 percent of insolation is directly absorbed Factors Influencing Temperature by dust particles and water vapour. Nearly 1. Latitude: In general the temperature 50 percent of this absorption occurs in the decreases from the equator to the poles as lower 2 km of air. per the altitude of the mid-day sun. 2. Conduction: When two bodies of unequal 2. Altitude: Temperature falls by 6.5° C for temperature are in contact with one every 1 km ascent. another, there is a www.OnlineIAS.com flow of energy from the warmer to the cooler body, until both the 3. Ocean Currents: Warm ocean currents, bodies attain the same temperature. Since moving polewards, carry tropical warmth air is very poor conductor of heat, it affects into the high latitude. This warming only the lowermost layer of the air. It is influence is very marked in latitudes 40° to least important in the heat transfer for the 65° on the west side of the continents, atmosphere as a whole. especially along the sea-board of Western Europe. Cold currents have fewer effects 3. Terrestrial Radiation: Radiant solar energy upon temperature because they usually lie reaches the earth’s surface in the form of under offshore winds. However, there are short electro-magnetic waves but is radiated some exceptions e.g. the coast of Labrador, in the form of long waves or infrared where the summer temperatures are radiation. Gases and water vapour are lowered by on shore winds which blow over almost transparent to short wave radiation. the cold Labrador current. Thus atmosphere receives a larger part of

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4. Distance from Sea: The sun’s heat is Between January and July all the isotherms absorbed and released more slowly by in the northern hemisphere move northward. water than by the land. So the sea-adjoining This movement of isotherm is greater over the areas experience warming and cooling land than over the oceans. The highest effects. The climatic regions whose temperatures for both January and July are over temperatures are influenced greatly by the the continents. The isotherms bend poleward sea are called “maritime or oceanic or over the ocean but equatorward over the insular climate”. Climate whose continent in January. The isotherms bend temperature is greatly influenced by the equatorward over the ocean but poleward over remoteness from the sea are called the continents in July.

“continental climate” The seasonal changes are less marked over 5. Winds: In temperate latitudes, prevailing the southern continents than over the northern winds from the land lower the winter ones. The range of temperature increases from temperature but raise the summer the equator to the poles. The coastal regions have temperature and the prevailing winds from a smaller range of temperature than the the sea raise the winter temperature but continental interiors. The range of temperature lower the summer temperature. In tropical on the eastern sides of Asia and North America latitudes, on-shore winds modify the is greater than on the Western side in the same temperature of the coastal regions. Local latitude. winds sometimes produce rapid upward or downward changes in the temperature. Temperature Anomaly: Temperature varies even along the same parallel of latitude because 6. Cloud Cover and Humidity: Clouds reduce of the factors like altitude, land and water the amount of solar radiation reaching the contrasts, prevailing winds and ocean currents. earth’s surface and the amount of earth The difference between the mean temperature radiation leaving the earth’s surface. The of any place and the mean temperature of its heavy cloud cover of equatorial regions parallel is called the Temperature Anomaly or doesn’t allow a day temperature over 30°C. Thermal Anomaly. It therefore, expresses In hot desert the absence of clouds results deviation from the normal. in very high day temperature of over 38°C and clear sky allows the earth heat to escape Inversion of Temperature: Air temperature freely resulting in fall of temperature up to also varies according to the altitude. At higher 20°C at night. altitudes air becomes less dense; it is unable to absorb heat, resulting in colder air temperature. 7. Aspects: South facing slopes are warmer The normal drop of temperature with height is than north-facing slopes in the Northern known as normal lapse rate which is 6.4°C per km Hemisphere while in the Southern on an average. Temperature inversion is the Hemisphere the reverse is true. In the high situation where there is increase in temperature latitude the mid-day sun is at a low angle with height before beginning to drop into the in winter and hence blocks of flats are normal lapse rate. In cases where the usually built far apart to enable all the flats www.OnlineIAS.comtemperature remains the same with increase of to receive some sunshine. altitude, the layer of atmosphere is called 8. Length of Day: The length of day also Isothermal. influences the temperature. 9. Amount of Dust and Other Impurities in Humidity

the Air: In the industrial areas and large It refers to the content of water vapour urban centres, the polluted particles are present in air in gaseous form at a particular time abundant in the air. These particles not only and place. It is measured through an instrument absorb larger amount of insolation but also called ‘hygrometer.’ greatly absorb the terrestrial radiation. Hence these areas show larger temperature • Absolute Humidity: The total weight of than the surrounding areas and are moisture content or water vapour per converted into “Heat Islands”. volume of air at definite temperature is

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called absolute humidity. particles or aerosols and these particles are • Specific Humidity: It is defined as the known as “hygroscopic nuclei”.

mass of water vapour in grams con- Condensation in Atmosphere: The cooling tained in a kilogram of air and it repre- needed to produce condensation can occur in a sents the actual quantity of moisture number of ways: present in a definite air. 1. Relatively warm moist air moving over a • Relative Humidity: It is defined as a ratio of the amount of water vapour colder surface. actually present in the air having defi- 2. The mixing of warm, moist unsaturated air nite volume and temperature (i.e. abso- with colder unsaturated air. lute humidity) to the maximum amount 3. Radiative cooling from the land surface. the air can hold at that temperature (i.e. 4. Upward motion of air. humidity capacity). Dew point: It is the temperature at which a Condensation Nuclei: The particles which parcel of air would have to be cooled in order to serve as condensation nuclei are hygroscopic, reach saturation. The favourable conditions are that is, they have affinity for water. moist air, light winds and clear night skies to Adiabatic Lapse Rate: The rate at which ensure maximum cooling by radiation. temperature decreases in rising and expanding as parcel is known as the adiabatic lapse rate. Evaporation: Until condensation occurs, temperature fall at Evaporation can be defined as the process by the rate of about 9.8°C per/km. This is known which liquid water is converted into a gaseous as dry adiabatic lapse. state. Evaporation can only occur when water is available. It also requires that the humidity of Fog the atmosphere be less than the evaporating It is microscopically small drops of surface (at 100% relative humidity there is no condensed water suspended in the air near the more evaporation). The evaporation process earth surface in sufficient number. It reduces the requires large amounts of energy. For example, horizontal visibility to less than 1 km. For aviation the evaporation of one gram of water at a purpose the reporting of fog is done only when temperature of 100° Celsius requires 540 calories the visibility is less than 9 km. On the basis of of heat energy (600 calories at 0° Celsius). appearance the fogs may be classified as- Condensation: 1. Smog: It is formed in the polluted air of large industrial centres having large In this process the water vapour is changed number of soot and dust particles, generally into liquid state. If air is cooled below its dew dirty and mixed with smoke. point, some of air’s water vapour becomes liquid. 2. Haze: It limits the visibility between 2 km Thus any further cooling of saturated air starts and 5 km. the process of condensation. Condensation depends upon two factorwww.OnlineIAS.coms - relative humidity of 3. Mist: It is intermediate between fog and air and degree of cooling. haze (visibility between 1 and 2 km). 4. Smaze: It is an admixture of smoke and Necessary conditions for condensation are: haze. 1. The air must be saturated. Saturation 5. Frost-Smoke: It is formed in the Arctic occurs either when the air is cooled below region when the air temperature falls much the dew point or when vapour is added to the below the freezing point. It is kind of fog air. having innumerable ice particles and super- 2. There must be a surface on which the water cooled water droplets is formed by the vapour may condense. For dew or frost, process of condensation. It generally takes solid objects at the ground do this work. place on the surface of water bodies and But when the condensation occurs in the later carried over the land by winds. air, the surface is provided by the dust

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Zero Visibility: When the object cannot be sharp outlines; develop vertically in the seen easily beyond 25 m. form of rising mounds; generally found in the day time over land areas; they dissipate at ‘9’ Visibility: When the object can be seen night. easily upto 50 km 4. Cumulo-nimbus: Heavy and dense cloud Clouds in the form of anvil; they are associated with heavy rainfall, thunder, lightning and Clouds are aggregates of innumerable tiny hail; have flat top and a flat base; it water droplets, ice particles or mixture of both obstructs the sun. in air generally above ground surface. On the basis of height clouds are classified as under: Precipitation

It is the process by which condensed water A. High Clouds (mean height 6 to 13 km): vapour falls to the earth’s surface as rainfall, 1. Cirrus: Detached clouds; fibrous (hair like) snowfall and other forms. On the basis of its silky appearance composed of ice crystals; origin, precipitation may be classified into three do not give precipitation. main types: 2. Cirro-cumulus: Thin, white patch; sheet or 1. Convectional Precipitation: It is caused layer of cloud; often connected with cirrus when moist winds are drawn into the or cirro-stratus clouds; when arranged convection currents of a hot region. It uniformly it forms a “mackerel sky”. generally occurs in equatorial region. The 3. Cirro-stratus: Transparent, whitish cloud thundery rain of a summer afternoon is a of fibrous or smooth appearance; produces typical example. “halo” phenomena around the sun and 2. Orographic Precipitation: It is caused by moon; mainly formed of ice-crystals. the surface relief of the land, mainly, by the presence of mountain range. There is B. Middle Clouds (mean height 2 to 6 km.): heavy rain on the windward side. 1. Alto-cumulus: Do not produce “halos”; Cyclonic Precipitation: It is associated with have dark shading on their under surface; the passage of a cyclone or depression. also referred as “sheep clouds”; composed of super-cooled liquid droplets. Forms of Precipitation

2. Alto-stratus: The sun may be totally Rain: Of liquid water particles in the form obscured but “halos” are never seen; of drops of more than 0.5 mm dia. shadow on the ground is never cast; Drizzle: Fine drops of water (diameter less precipitation may fall either as fine drizzle than 0.5 mm), very close to one another. or snow. Snow: White and opaque grains of ice. 3. Nimbo-stratus: A low cloud form and may be thousands of feet thick; it is a rain, Sleet: Mixture of rain and snow snow or sleet cloud;www.OnlineIAS.com never accompanied by Hail: small pieces of ice with a diameter lightening, thunder or hail. ranging from 5 to 50 mm.

C. Low Clouds (mean height 0 to 2 km.): Rainfall

1. Strato-cumulus: A low cloud layer When precipitation is in the form of water consisting of large lumpy masses or rolls of drops, we call it rainfall. Only when dull grey colour with brighter interstices. temperature of water vapour is above 0°C, 2. Stratus: A fairly uniform base which may give rainfall will occur. At sub-zero level drizzle, ice-prisms or snow grains; sky may temperatures, snowfall will occur. Main be completely covered by this cloud; difficult determinants of rainfall are- latitude, distance to differentiate between high fog and from the sea, direction of winds, proximity of stratus. mountains and seasons. The regions of heavy 3. Cumulus: Detached dense clouds with rainfall in the world are - Equatorial regions,

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Tropical Monsoon regions and mid-latitude West (a) The regions of heavy precipitation (more than 150 cm.): Margin regions. Regions of low rainfall (below 25 cm annual) are- tropical desert, mid-latitude 1. Equatorial regions: The Amazon and the deserts and Polar Regions. Congo basins, Malaysia, Indonesia and New World Distribution of rainfall: After Guinea. examining the latitudinal pattern of distribution 2. Tropical Monsoon regions: Parts of India, of rainfall it will be seen that the maximum is South-east Asia and South China. received in the equatorial zone and the minimum 3. Mid-latitude West Margin regions: Coastal is in the Polar Regions. A secondary maximum regions of British Columbia, North-west lies in the belt of 40°–60° N and 40°–60° S and a Europe, South Chile and South Island of secondary minimum occurs around 30° N and New Zealand. 30° S latitudes. This pattern of rainfall distribution is closely related to the distribution of (b) Moderate rainfall of 100 to 150 cm per major pressure belts of the world. The two zones year is received in the eastern margins of of maximum precipitation are related to the continents in the trade-wind belt. These are equatorial low pressure and sub-polar low the sub-tropical eastern margins of China, the pressure. These low pressure belts are regions of U.S.A., Brazil, South Africa and Australia. ascending air and therefore precipitation is (c) Regions of extremely low rainfall (less than greater than elsewhere. The belts of minimum 25 cm.): precipitation are zones of polar high pressure 1. Tropical deserts Western margins of and subtropical high pressure. As the capacity continents in the trade wind belt– to hold water vapour decreases sharply with Californian desert in the United States, temperature, precipitation is generally higher in Atacama, Kalahari, southern Africa, the low latitudes than in the high latitudes. Sahara, Arabia and then in Afro Asia, and This broad latitudinal pattern is modified by West Australia. the distribution of continents and oceans, and 2. Mid-latitude desert in the interiors of large the direction of prevailing winds. Winds blowing continents such as Asia and North America. from the oceans towards the landmasses are 3. Polar regions. called on shore winds. Such winds are moisture laden and give rainfall along the coast. When Pressure & Wind winds blow from the land masses towards the oceans, they are called off-shore winds. These Wind can be defined as air in motion. The are not rain bearing winds. principal cause of winds is the difference in pressure. Air always moves from areas of high In the belt of trade winds, there is maximum pressure to those with low pressure. The slope precipitation in the eastern margins of continents of the pressure from high to low is known as the as the easterly winds blow from the oceans. In pressure gradient and the direction of this this belt rainfall decreases towards the west. The gradient decides the direction of the winds. western margins of continentwww.OnlineIAS.coms are deserts. These are the tropical deserts of the world. Owing to the earth’s rotation, all the winds are deflected to the right in the northern In the mid-latitudes, the westerly winds give hemisphere and to the left in the southern maximum “rainfall to the western margins of hemisphere. This is referred to as the Ferrel’s Law continents. Rainfall decreases gradually towards and the force occuring due to the rotation of the the east and the interiors of large continents are earth is called the Coriolis force. dry. These are mid-latitude deserts. Buys Ballot’s Law: In northern hemisphere, if The location of mountain ranges with a person stands with his back to the wind, low reference to prevailing winds also influences the pressure lies to his left and high pressure lies to distribution of precipitation. Maximum his right. In S-Hemisphere it is reversed since the precipitation is received where the mountain Coriolis deflection is to his left. ranges lie right across the path of prevailing winds e.g. the Western Ghats in India.

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Types of winds: seasonal reversal of direction. The monsoon winds blow over India, Pakistan, Bangladesh, (i) Planetary winds or Prevailing winds; Trade Burma, Sri Lanka, Arabian sea, Bay of Bengal, winds, Westerlies and Easterlies. S.E. Asia, N. Australia, China and Japan. (ii) Periodic winds: Land breeze, Sea breeze & Monsoon winds. Summer Monsoon: During summer, a thermal low is developed over southern Asia in (iii) Local winds: Loo, Fohn, Chinook, Mistral the lower levels of the atmosphere. From the and Jet Streams. Indian Ocean and the south western Pacific, (iv) Atmospheric Disturbances: Tropical warm humid air moves northward and north Cyclones and Temperate Cyclones. westward into Asia passing over India, Indo China and China. This summer monsoon is I. Planetary Winds: The wind systems that accompanied by heavy rainfall in south-east are bound to occur at the global level on any Asia. planet having an atmosphere and rotating about its axis. The specific characteristics of trade Winter Monsoon: The Winter monsoon is a winds, Westerlies and Easterlies may be gentle drift of air in which the winds generally determined by several conditions but the broad blow from the north east. Retreating monsoon features are constant over the globe. causes sporadic rainfall especially in the north- eastern parts and Tamil Nadu coastal areas of Trade Winds: These winds blow from the India. Outside India, in the East Asian countries subtropical high pressure towards the equatorial e.g. China and Japan, the winter monsoon is region of low pressure regularly throughout the stronger than the summer monsoon. year. It brings little rain except on the line of convergence of the two trade wind systems. III. Local Winds: There are winds that develop as a result of local conditions in Westerlies: The Westerly winds are those temperature and pressure of air. They affect which blow with great frequency from the Horse small areas in the lowest levels of Troposphere. latitudes towards the Polar region throughout the year with varying intensity and cause rain Loo: A very hot and dry wind (hot wave) in near the polar regions. Westerlies are stronger the North Western India and Pakistan which in the Southern Hemisphere because of the vast blows from the west in the afternoon of May and expanse of ocean waters. Owing to their June and may cause sunstroke. ferocious nature, they are also described as Chinook and Fohn: Warm and dry local “Roaring Forties”, “Furious Fifties” and winds, also called ‘snow-eater’, blow on the “Shrieking Sixties” in southern hemisphere. leeward sides of the mountains. These are called Doldrums: Also known as Intertropical Chinook in the USA and Fohn in Switzerland. convergence, it is the equatorial belt of low Harmattan: The warm and dry winds atmospheric pressure where the north-east and blowing from north-east and east to west in the south east Trade winds converge. It is a region eastern parts of Sahara desert are called of calmness, the calm periodically broken by www.OnlineIAS.comHarmattan. Similar winds are called ‘brick storms, accompanied by heavy rains. fielder’ in Australia, ‘blackroller’ in USA, Horse Latitude: They are the subtropical ‘Shamal’ in Mesopotamia and Persian Gulf and belts of high atmospheric pressure over the ‘Norwesters’ in Newzealand. oceans (near 30° latitude) between the regions Sirrocco: It is a warm, dry and dusty wind of trade winds and Westerlies. They are regions which blows in northward direction from of calm, light variable winds and dry air. Sahara desert and after crossing Mediterranean II. Periodic Winds: Sea reaches Italy, Spain etc. Similar winds are known as ‘Khamsin’ in Egypt, ‘Gibli’ in Libya, Monsoon: The word monsoon has been ‘Chilli’ in Tunisia, and ‘Simoom’ in Arabia. derived from the Arabic word “Mausim” which means season. The monsoon winds thus refer to the wind systems that have a pronounced

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Local and Regional Winds

Winds Region / Country Nature 1. Fohn Alps / Europe (Germany) Dry / Warm 2. Chinook Rockies, U.S.A. & Canada Dry / Warm 3. Mistral Alps /France to Mediterranean Sea Dry / Cold 4. Sirocco N. Africa / Sicily / Italy Dry / Hot 5. Khamsin Egypt / N. Africa Dry / Hot 6. Harmattan W. Africa / Ghana / Nigeria Dry / Hot 7. Norwesters Bengal / Assam / India Moist / Hot 8. Berg South Africa Dry / Cold 9. Pampero Argentina Dry / Cold 10. Zonda Chile / Peru / Brazil/ Argentina Dry / Warm 11. Brick Fielder Australia Dry / Hot 12. Buran Siberia / Russia Dry / Cold 13. Bora Italy / Yugoslavia (To Adriatic Sea) Dry / Cold 14. Southerly Buster Australia Dry / Cold 15. Samun Persia / Iran Dry / Hot 16. Nevadas Ecuador Dry / Hot 17. Norwesters New Zealand (South Island) Dry / Hot 18. Leveche Algeria / Morocco Dry / Hot 19. Blizzard Siberia, Canada and USA. Dry / Cold (Snow laden) 20. Bise France Dry / Cold 21. Levanter Spain Dry / Cold 22. Santa Ana USA Dry / Warm 23. Yamo www.OnlineIAS.comJapan Dry / Warm 24. Tramontane Central Europe Dry / Warm

Diurnal Variation in are caused by the thermal differences between the land and water surface. Atmospheric Circulation Sea Breeze: Takes place during the day Diurnal wind systems occur frequently in when a local thermal low develops over the land many tropical areas. They also occur in other with the winds blowing from the sea towards the areas but rather irregularly and less frequently. land. There are two major types of diurnal wind systems: Land Breeze: Take place during the night when the land cools off rapidly while the sea is 1. Land and Sea Breezes: These occur along still warm. Then the winds blow from the land the coast or near large water bodies. They towards the sea.

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2. Mountain (Katabatic) and Valley 6. The source of energy for the maintenance (Anabatic) Winds: During the day when of tropical cyclones is the latent heat of insolation is intense the more exposed hill condensation. slopes are heated more than the valley C. Tornadoes: bottoms. Thus winds blow upward from the valley. These are valley or anabatic 1. The most violent storms of lower (upslope) winds. The high lands cool off troposphere. rather rapidly because of terrestrial 2. The funnel shape cloud extends radiation losses. Cold and dense air then downwards from the base of cumulonimbus drains downslope into valleys. Such cold cloud layer. winds are known as mountain or Katabatic winds. 3. Tornadoes which occur in conjunction with scattered thunderstorms are usually short- Cyclones lived and have irregular paths. 4. The circulation of wind is usually in a This is a depression in a mass of air whose counter clock wise direction; wind velocities isobars form an oval or circular shape with low are very high almost about 100 m/sec. pressure at the centre. The air converges at the centre and then rises. The winds rotate anti-clock 5. Occur frequently east of the Rockies wise in the northern hemisphere while in the Mountains in the Mississippi Basin in USA, southern hemisphere the circular movement of in eastern India and east of the Andes winds is in a clockwise direction. Moving Mountain. cyclones are of three types: 6. At sea, tornadoes become water spouts having same characteristic except that they A. Extratropical Cyclones: are small in diameter.

1. Typical of middle and high latitudes; Anti-cyclones usually called a depression. 2. This cyclone varies in diameter from 200 It is opposite to the cyclones where two types km to 300 km. of anticyclones are observed: 3. Appearance may be circular or elongated 1. Relatively Stationary, also called as warm or may be broad shallow, week depressions. anticyclones. 4. Usually travel in groups or “Families” from 2. Travelling anticyclones, which are also the West to East. called as cold anticyclones, are mainly 5. Average speed is about 30-50 km per hour. found in the high latitude within continental polar air. B. Tropical Cyclones: 3. Barometric pressure is highest at its centre and decreases outward. Anticyclonic wind 1. Tropical Cyclones are found in low system blows out from the centre and latitudes over oceans. www.OnlineIAS.combecause of the Coriolis Effect it has a 2. It is almost circular centre of extremely low clockwise circulation in the Northern pressure into which winds spiral. hemisphere and counter clockwise in 3. The diameter of the storm ranges from 160 Southern hemisphere. to 650 km and the velocity of the wind Beaufort scale: In 1806 “Admiral Beaufort” varies from a minimum of about 120 to proposed a scale for estimating the wind velocity 200 km per hour. and developed the Beaufort scale. 4. The life span of a tropical cyclone is about a week and the storm travels at the rate of 15-30 km per hour. 5. Tropical cyclones are characterized by violent winds and heavy rains.

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Beaufort Wind Speed Common effects No. (Mph) 0 Calm 0 Smoke rises vertically. 1 Light air 2 Wind vanes not applicable. 2 Light Breeze 5 Wind felt on the face. 3 Gentle Breeze 10 Leaves & small things in motion. 4 Moderate 15 Raises dust & loose paper & small branches moved. 5 Fresh Breeze 21 Wavelets in water. 6 Strong Breeze 28 Large branches in motion. 7 Moderate Gale 35 Whole tree in motion. 8 Fresh Gale 42 Breaks twigs of trees 9. Strong Gale 50 Slight structural damage 10 Whole Gale 59 Tree uprooted; great damage 11. Storm 69 Widespread damage 12 Hurricane > 75 Most destructive.

Points to remember

1. “Eye” is the central low pressure core of 7. “Stevenson Screen” is a Meteorological tropical cyclone. shelter. 2. In the tropical cyclone the pattern of isobar 8. Weather cock is used to ascertaining “wind is “circular”. direction”. 3. Willie-Willie is a type of tropical cyclone 9. The condensation at dew point below 0°C of Australia. produces frost. 4. Chinook is also known as “Snow-Eater”. 10. The scattering of light by dust particles is known as “Tundal effect”. 5. “Squall” is a very short lived fast wind. 11. Cirrostratus is a type of cloud around 6. Frozen raindrops are called “Sleet”. which a halo is created.

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CLIMATIC CLASSIFICATION

Climate can be classified on the basis of Annual range of temperature is greater in temperature, precipitation, evaporation and the interior than along the coast. their seasonal characteristics. The classification Annual rainfall may exceed 150 cm. along scheme of W. Koppen is the most popular system the coast and universally accepted. A classification of the world climatic types is given ahead: Characteristics: Strongly developed dry season and the rainfall of the driest mouth 1. Tropical Rain Forest/Equatorial Forest Type is less than 6 cm. Great contrast in Extent: 5°N to 5°S; Amazon Basin, Zaire temperature between summer and winter. Basin, Malaysia, Indonesia. 4. Tropical Deserts Average daily temperature: 25°C Extent: Western margin of the continent; throughout the year N. America- Colorado Desert, Mexican Annual range of temperature: Less than Desert; Africa - Sahara & Kalahari Desert; 5°C S.W.- Asia - Arabian, Iranian & Thar Daily range of temperature: Less than Deserts; S. America- Atacama Desert; 10°c, due to high % of cloudiness. Australia- Great Australian Desert. Rainfall: Convectional, throughout the Mean monthly temperature is 36°C in year. No dry season. summer and 15°C in winter. Annual rainfall: 150 to 200 cm. Diurnal range of temperature is very high. Characteristics: Hot wet condition Annual rainfall: It is a region of throughout the year favours rich descending air so precipitation is scanty. It vegetation. remains very hot during the day (45°C) and quite cool at night (15°C). Annual rainfall 2. Tropical Grassland/Savanna Type is less than 20 cm. Extent: 5°N to 15°N & 5°S to 15°S; Africa, East 5. Mid-Latitude/Temperate Deserts & central S. America, Transitional zone between Monsoon and desert climates of Extent: Tibet, Mongolia, Gobi, Patagonia, Australia. Parts of Soviet, Central CIS. Monthly mean temperature: 32°C in Average annual temperature: above 18°C summer and 20°C www.OnlineIAS.comin winter. Rainfall: scanty. Annual rainfall: 50 to 100 cm. Charactereristic: Winter is colder because Characteristics: Distinct dry season in of its interior location. Some are inter- winter. Rainfall is in summer owing to mountain deserts. convectional ascent of air. 6. Tropical Dry-hot Steppe They have tropical grassland with Extent: N.Australia, Arabia, Rajasthan, scattered trees. Deccan Plateau, S.African Plateau, North Argentina. Llanos: Colombian Highland. Annual rainfall: 30 cm, maximum in Campos: SE highland of Brazil, summer. Granchaco: Argentina & Uruguay. Charactereristic:Climate is semi-arid characterized by grasslands. Savanna: Australia and Africa. 7. Mid-Latitude Dry-cold Steppe 3. Tropical Monsoon Type Extent: Ukraine W. Siberia, Western U.S.A Extent: South-east and East Asia, N. Annual rainfall: less than 30 cm, maximum Australia, India, Myanmar, Thailand and in summer. South China.

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Charactereristic:It has semi-arid climate 11. Snowy Forest Climate with moist Winter/ with grasslands. Taiga 8. Mild Humid Climate with no Dry Season/ Extent: beyond 60° N in Europe, Asia and West European Type N. America. Extent: South of 45°S, Western margin Annual rainfall: 30 to 40 cm; both in between 45°N and 60°N; N.W.-Europe winter and summer; No dry season. including British Isles, west coast of Characteristics: Summers are short and Canada, S.Chile, Southern New Zealand, warm, warmest month temperature is 10°C to Tasmania. 15°C. Rainfall of driest month: more than 3 cm. Winter are long and severe, coldest month Monthly mean temperature: 5°C in winter temperature below-3°C. Have coniferous and 15°C in summer. forest vegetation. Annual range of temperature: 10°C. 12. Snowy Forest climate with Dry Winter/ Winters are milder than the similar latitude in Manchurian Type the eastern margin of the continent. Extent: Eastern Siberia, Northern China, Annual rainfall: 75 to 100 cm. No dry Part of Japan, Korea, N.E. -USA, E- Season as the westerly winds blow from Canada, the ocean throughout the year. Rainfall is Temperature range is 20°C in summer and mostly of cyclonic origin. 5°C in winter 9. Mild-Humid Climate with a Dry Winter/ Annual rainfall: 50 cm. to 75 cm. Summer China Type is the season of rainfall, winter is dry. Extent: Along the eastern margin of the Vegetation consists of mixed forest of continent in sub-tropical belt; 25°-35° in deciduous and coniferous trees. both the hemispheres; Central China, S.E.- 13. Tundra Climate USA, South Bengal; Eastern Argentina, S.E.-Africa, S.E.-Australia, S-Brazil, S-Japan. Extent: Arctic Ocean coast, Iceland, Greenland Annual rainfall: 100 cm, maximum in Mean temperature of the warmest month: summer. Warmest summer month has ten 0°C to 10°C times more rainfall than the driest winter month. Winter is a dry season as in winter, Vegetation: Mosses, Lichens. cold winds blow from the interior landmass. Annual range of temperature: 40°C to These areas are exposed to tropical cyclones. 50°C 10. Mid-Humid Climate with Dry Summer/ Annual rainfall: 20-25 cm. Mediterranean Type Characteristics: Summer is short, ground Extent: 30° to 45° L on western side of the may be snow free. During long winter soil continent in both hemispheres; Around the moisture freezes and snow covers the land Mediterranean sea, in S. Europe, N. Africa, totally. California coast, Centrawww.OnlineIAS.coml Chile, Cape of 14. Perpetual Forest Climate/Ice-cap Type Good Hope, S.E. -Australia Extent: Antarctica, Greenland. Rainfall of driest month of summer: less than 3 cm. Winter is the wettest month; Temperature is always below 0°C, 70% rainfall in the 6 winter months. throughout the year. Winter- continuous night and summer- Monthly mean temperature: 20°C in continuous days summer and 10°C in winter. 15. High Mountain Type Annual rainfall: 40 to 90 cm only in winter (Cyclonic rainfall). Extent: On high mountain slope of both hemispheres. Himalayas and Andes have Off shore trade winds blow in summer; vertical zonation of climate from tropical they are dry and give no rainfall. to ice-cap type. Windward slope receives Local winds like Sirocco, Mistral, Boro are heavy rainfall while the leeward sides are prevalent. dry. In the N-Hemisphere southern slopes are warmer.

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HYDROSPHERE

All the water of the earth including the oceans, Ocean Area in Percentage lakes, rivers, ice sheets and the water in the sq. km of sea area atmosphere is called hydrosphere and it covers about 71% of the earth's surface. The ocean Pacific 1, 66,240,000 46.0 predominates over land areas in the S-Hemisphere Atlantic 86,560,000 23.9 far more than that in the N-Hemisphere. Major Oceans Indian 430,000 3.7

The Pacific Ocean: It is the largest and deepest Profile of Ocean Floor ocean covering one third of the globe. Its average depth is 4200 m. The deepest parts are the The ocean basins are in many ways similar Philippine Trench about 10,380 m. and the Marina to the land surface. There are submarine ridges, Trench about 10,800 m. The Pacific -Ocean has a plateau, canyons, plains and trenches. The great string of volcanoes along the coastal margins of variety of relief is largely due to the interaction the conti-nents known as 'The Ring of Fire'. of tectonic, volcanic, erosional and depositional

The Atlantic Ocean: Though the Atlantic is processes. In general the ocean floor can be smaller than the Pacific, its total coastline is more divided into four major divisions - the continental shelf, the continental slope, the than that of the Pacific and the Indian Ocean continental rise and the Abyssal Plain. combined. There is a long submarine ridge run- ning north to south in the middle of Atlantic. It Continental Shelf: It is the land portion, is the greatest mountain chain in the world submerged under sea water and is a transitional (16,000 km long). It is known as the Dolphin zone between the land and the actual sea bottom. Ridge in the North Atlantic and the Challenger 1. The isobath of 100 fathoms (around 200m) Ridge in the South Atlantic. There are also con- demarcates the continental shelf. tinental islands such as the British Isles, New- foundland, the West Indies etc. The Atlantic is the 2. The average width is about 70 km. and the greatest commercial highway of the world. mean slope is less than 1°.

Indian Ocean: It is small in size but has an 3. About 7.5 percent of the total ocean area is average depth of 4,000 m. The two great bays covered by it. on either side of the peninsulawww.OnlineIAS.com of India, namely 4. It is almost absent in the eastern Pacific the Bay of Bengal and the Arabian Sea belong to ocean, especially in South America. the India Ocean. The Indian Ocean is dotted with thousands of small islands some of which are of 5. At the eastern coast of USA it is about 120 coral formation, e.g. the Maldives and km wide and also very wide on the eastern Lakshadweep islands, while other like the coast of India. Mauritius and the Reunions are volcanic. Sri 6. Individually it covers about 13.3% part of Lanka and Malagasy are continental islands. Atlantic Ocean, 5.7% of Pacific Ocean and Arctic Ocean: It is found around the North 4.2% of Indian Ocean. Pole. It covers only one thirtieth of the sea area. It is almost completely covered with ice to a 7. It is the area of terrigenous deposits i.e. depth of about 3 m. sediments are derived from land.

Antarctic Ocean: The remaining area of the 8. They provide the richest fishing ground in sea is included in the Antarctic Ocean surround- the world. ing the Antarctic Continent.

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9. About 20% of world petroleum and natural gas are found here.

Continental Slope: It lies at the edge of the continental shelf, generally up to the depth of 2000 fathoms (3660 m) from the mean sea level.

1. It has a steep slope with the angle of slope varying from 2° to 5°.

2. It covers about 8.5% of the total oceanic

area and individually about 12.4% of the Atlantic Ocean, 7.1% of the Pacific Ocean and 6.5% of the Indian Ocean.

3. The continental blocks are supposed to end 3. All the above features are volcanic in origin, at the site of continental slope. very common in Pacific Ocean. 4. The continental slope along the many coasts of the world is furrowed by deep canyons Submarine Trenches or Deeps: A long like trenches terminating as fan-shaped narrow and steep sided depression on the ocean deposits at the base. floor is called trench. These are the deepest part of the ocean. Continental Rise: The place where the 1. They lie along the fringes of the deep sea continental slopes end, the gentle sloping plains and usually run parallel to the continental rise begins. The average slope is bordering fold mountains or the island between 0.5° and 1° & its general relief is low. With claims. increasing depth the Continental Rise becomes virtually flat and it merges with abyssal plain. 2. They are believed to have resulted from

Abyssal/Deep Sea Plains: Beyond faulting or down folds of the earth crust and so tectonic in origin. Continental Rise, it is found at the depth of 3000 to 6000 m. They cover about 40% of the total 3. They are most common in the Pacific Ocean ocean floor and generally are bounded by hills like "Mariana Trench" off the Guam Island (ridges) on the seaward side. They are almost flat Chain which is deepest (11 km) in the with a gradient less than 1:100. The irregular world. topography of the abyssal plain are buried forming relatively flat areas due to large supply Submarine Canyons: These are the deep of sediments. gorges on the ocean floor and are restricted to the continental shelves, slopes and rises. Submarine Ridges: These are the mountain ranges on the ocean floor and some of them are 1. Some canyons begin at the edge of the the largest mountain system on the earth. continental shelf and extend down the 1. A large number owww.OnlineIAS.comf submarine ridges are continental slope. For example - placed centrally in the oceans. "Oceanographer Canyon" near New England. 2. At some places their summits may rise above the sea level forming islands. 2. Some canyons have dendritic appearance like off the east coast of Southern California. Abyssal Hills: A deep sea floor also contains numerous isolated abyssal hills, sea- 3. Some begins at the river mouth and extends mounts and guyots. over the continental shelf as "Zaire", 1. A submarine mountain peak rising more "Mississippi" and "Indus" canyons.

than 1000 m above ocean floor are known Bank, Shoal & Reef: Banks are almost flat as "seamount". topped elevation located in the continental 2. Flat topped seamounts are known as margin. Shoals are detached elevation with "Guyots". shallow depth. Reefs are the mound or rocky elevation like ridges made of organic deposit.

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1. The depth of water is relatively small in Trenches: Sunda Trench, Valdivia Deep, Jef- banks but adequate for navigation. frey deep 2. These are sites of rich fishing e.g. "Dogger Bank" (North Sea), "Grand Bank" (off ARCTIC OCEAN

Newfoundland). Ridges and Basins: Faeroe-Iceland Rise, East 3. Shoals are dangerous for navigation as they Jan Mayen Ridge, Spitsbergen Ridge, Greenland Basin, Norwegian Basin, N-Polar Basin are only 18-20 m below the sea level.

4. 'Great Barrier Reef' (off Queens land, Temperature Australia) is the largest reef in the world.

Horizontal Distribution of Temperature: The ATLANTIC OCEAN mean annual temperature of the surface water of

the oceans is 25°C varying from - 5°C to over 33°C. Ridges: Rio Grande Ridge, Wyville-Thomp- son Ridge, Newfoundland Ridge, Walvis 1. The temperature decreases as we move Ridge, Telegraphic Plateau, Sierra Leone Ridge, away from the equator. The average Raykjanes Ridge, Cape Swell, Dolphin Rise, temperature of ocean water is 26°C at the Challenger Rise. equator, 23°C at latitude 20°.

Basins: Labrador Basin, Iberian Basin, Cape- 2. The coldest month in the ocean is February Verde Basin, Guinea Basin, Sierra Leone Basin, and the warmest month is August in the Cape Basin, Argentina Basin, Agulhas Basin Northern Hemisphere and reverse in the Deeps & trenches: Moseley Deep, Buchanan Southern Hemisphere. Deep, Valdivia Deep, Romanche Deep, Puerto- 3. The highest temperature of ocean water is Rico Deep, Nares Deep found in enclosed or partially enclosed seas PACIFIC OCEAN in the equatorial areas e.g. a temperature of 38°C has been recorded in Red Sea Ridges: Albatross Plateau, Cocos Ridge, San- Felix-Juan Ridge, Hawaiian Swell, Marcus though the average temperature in summer is Necker Rise, Chatham Rise, Lord Howe Rise, only 29°C.

Norfolk Ridge, S. Tasmania Ridge 4. The temperature of the warm current is Basins: Aleutian Basin, E&W Caroline Basin, Fiji higher than the surrounding areas. Thus Basin, E. Australian Basin, Jeffrey's Basin, S W Gulf Stream does not allow the Norwegian Pacific Basin, SE Pacific Basin, Pacific Atlantic coast to freeze even in winter. Basin. 5. The prevailing winds deflect the warm and Trenches: Aleutian Trench, Kuril Trench, Phil- cold currents and cause change in ippine Trench, Cape-Johnson Deep, Nero Deep, temperature of the ocean water. So, in the Mariana Trench, Tonga-Kermadec Trench, tropical zone the western section of the Aldrich Deep, Brook Deep,www.OnlineIAS.com Planet Deep oceans are warmer than the eastern section owing to the influence of trade winds. In INDIAN OCEAN the Temperate zone the westerlies makes Ridges: Socotra-Chagos Ridge, St. Paul Ridge, the eastern section warmer than the Seychelles Ridge, Crozet Ridge, Crozet Ridge, western section. Kerguelen Ridge, Laccadives-Chagos Ridge, 6. The temperature decreases as we move Chagos St. Paul Ridge, Kergel-Gausberg Ridge, away from equator. Andaman Rise.

Basins: Somali Basin, Oman Basin, Natal Ba- Vertical distribution of temperature: sin, Mauritius Basin, Agulhas Basin, Andaman Though the sea temperature decreases with in- Basin, Cocos-Kelling Basin, E. Indian-Antarc- creasing depth, the rate of decrease is not uni- tic Basin form. The change in sea temperature below 200 m is negligible.

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Horizontal Distribution of Salinity Salinity I. Latitudinal Distribution: It decreases The salinity of the Ocean means the from Equator towards the Poles. The average degree of saltiness of the oceans. The average salinity of N-Hemisphere is 34‰while for S- salinity of the oceans is 35.3% i.e. about 35 Hemisphere it is 35‰. In general there is low parts of salt in 1,000 parts of water. In the salinity in equatorial zone, high in tropical Baltic Sea, where there is much dilution by belt, low in temperate zone and minimum in fresh water and melting ice, the salinity is sub-polar zone. much lower only about 4%. Very high salinity is recorded in inland seas and lakes. Lake van in Latitudinal Zones Salinity (%) Turkey records the highest salinity of 330%. 10-15 N 34.5-35 Red Sea (240%), Dead sea (238%), Great Salt Lake with (220%) are other areas of high 15-40 N 35-36 salinity. 40-50 N 33-34 The variation of salinity in the various seas and oceans is affected by: 50-70 N 30-31

1. The rate of evaporation. 10-30 S 35-36 2. The amount of fresh water added by precipitation, streams and icebergs; and 30-50 S 34-35 3. The degree of water mixing by currents. 50-70 S 33-34 • The origin of salinity is attributed to erosion of earth's crust by dissolving II. Regional Distribution: The amount of action of running water which causes salinity varies from ocean to ocean, mainly due erosion in the oceanic crust and volcanic to supply of fresh water, rapidity of evaporation ash which contains minerals like and water mixing tendency. The greatest Calcium, Boron, Iodine, etc. proportion of salt is found in two areas which lie about the Tropic of Cancer and the Tropic of • Salinity is excessive in region of high Capricorn. From these regions the salinity temperature, strong winds and less rain. decreases both towards equator and the poles. For example, it is lower in the equatorial Salinity of the inland seas and lakes is very high region due to high relative humidity. because of the regular supply of salt by the rivers • Influx of fresh water by rivers reduces the flowing into them and the evaporation makes salinity and so there is less salinity near their water continuously more and more saline. the mouths of rivers like Amazon, Congo, Niger, Ganga etc. Vertical Distribution of Salinity

• In spite of high temperature salinity is less 1. Salinity of the ocean decreases or increases is equatorial region because of his rainfall. towards the bottom according to the nature Around the Poles there is a belt of low of the water mass.

salinity because ofwww.OnlineIAS.com addition of fresh water 2. In high latitude salinity increases with in the form of icebergs and excessive depth due to dense water found at the snow falls. bottom. In the middle latitude salinity Oceanic Salt Ratio increases with the depth upto 200 fathoms and then it starts decreasing. Salt Name Percentage NaCl Sodium Chloride 77.8 3. At equator surface salinity is low but just MgCl2 Magnesium Chloride 10.9 below it greater salinity is found which again MgSO4 Magnesium Sulphate 4.7 decreases at the bottom due to presence of cold water mass. CaSO4 Calcium Sulphate 3.6 K2SO4 Potassium Sulphate 2.5 Ocean Deposits CaCO3 Calcium Carbonate 0.3 MgBr2 Magnesium 0.2 The unconsolidated sediments derived

www.OnlineIAS.com N. Kalyana Chakravarthy 62 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] from various sources, deposited at the sea Other Islands: Tasmania, Terra del Fuego, floors are called ocean deposits. The ocean Southampton. deposits are classified on the basis of their Important Gulfs and Seas Part of the Ocean location as terrigenous and pelagic deposits. 1. South China Sea Pacific Ocean Terrigenous Deposits: These are deposits of the continental shelf and slope. They consist 2. Caribbean Sea Atlantic Ocean of material derived from wear and tear of land, 3. Mediterranean Sea Atlantic Ocean the remains of animals and plants that live on the bed of the sea and volcanic material. On 4. Bering Sea Pacific Ocean the basis of size of rock fragments, the sediments are classified into gravel, sand and 5. Gulf of Mexico Atlantic Ocean mud. Mud is further classified as red, blue or 6. Sea of Okhotsk Pacific Ocean green mud on the basis of their colour. Volcanic deposits consist of sub-aerial and sub 7. East China Sea Pacific Ocean marine volcanic deposits. The organic deposits consist of shells and skeletons of animals living 8. Hudson Bay Atlantic Ocean in the continental shelf. 9. Sea of Japan Pacific Ocean

Pelagic Deposits: These deposits are 10. Andaman Sea Indian Ocean found in deep sea plains. They cover 75 per cent of the ocean area. The organic deposits consist 11. North Sea Atlantic Ocean of liquid mud known as 'ooze' which contain 12. Black Sea Atlantic Ocean shells of various organisms. They are subdivided into Calcareous ooze and Siliceous 13. Red Sea Indian Ocean ooze. The former contains Pteropod and Globigerina ooze. The latter consists of 14. Baltic Sea Atlantic Ocean Radiolarian and Diatom ooze. The inorganic 15. Persian Gulf Indian Ocean deposits contain Red Clay, which is formed from the decomposition of volcanic material 16. Gulf of St. Lawrence Atlantic Ocean which is carried out to sea and occupies the 17. Gulf of California Pacific Ocean maximum space of the ocean floor. 18. Irish Sea Atlantic Ocean World Islands 19. English Channel Atlantic Ocean

Atlantic Ocean Islands: Greenland, Baffin, 20. Bass Strait Pacific Ocean Ireland, Great Britain, Iceland, Hispaniola, Pico Island of Azores, Cuba, Cape Verde Island, Perks 21. Arabian Sea Indian Ocean

Projected Island, Bermuda Island, Ascension 22. Bay of Bengal Indian Ocean Island, St. Helena Island, Gough Volcanic Island, Newfoundland, West Indies.www.OnlineIAS.com Coral reefs & Atolls Indian Ocean Islands: Andaman & Nicobar, Madagascar, Zanzibar (all are the de- Corals are a kind of calcareous rock chiefly tached part of continental block), Lakshadweep made of the skeletons of minute sea organisms & Maldives (coral islands), Mauritius & Reunion called 'polyps'. Coral reefs and atolls are formed Island (Volcanic), Sumatra, Java, Sri Lanka, due to accumulation and compaction of skeletons of these lime secreting organisms. Pacific Ocean Islands: New Guinea, Conditions for Growth of Coral Reefs Borneo, Honshu, Hokkaido, Honshu, Shikoku, Celebes, South Island and North Island (New 1. The coral and the associated organisms and Zealand), Luzon, Mindanao, Sakhalin, algae which are the most common reef

Atlantic Ocean Islands: Ellesmere, Victoria, builders are con-fined to the tropical belt. The Banks, Devon, Melville, Axel Heiberg, water temperature must not fall below 20°C and not exceed 35°C; the most favourable is 23°C to 25°C.

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2. Corals can live only in saline water, and in Maldives, Funafoothis Atoll of Ellice. for their proper growth the average salinity Geographical Distribution of Coral Reefs should be between 27 to 40%. 1. Coral reefs are limited to the tropical seas 3. For growth of coral the depth of the water and are found almost entirely between should not exceed 200m. Most vigorous latitudes 30°N and 25°S. growth is confined to shallow water less than 50 m. deep. 2. Rich growth of reefs is found off the eastern coasts of North America and Australia. 4. Corals also require sediment-free, clean water which is disturbed by ocean waves and 3. On coasts where the rivers bring large currents is beneficial for the corals. quantities of sediments from the land, corals are not found e.g. coasts of South America. 5. In the open seas it is necessary to have platforms which may act as foundations 4. The coral reefs are most common in the for the corals. These platforms should not Pacific and the Indian Ocean, due to their be deeper than 90 m. shallow, warm and clean water.

The coral reefs are classified on the basis of 5. The most important area of coral reef nature, shape and mode of occurrence into (i) growth lies in the seas off the east coast of Fringing reef (ii) Barrier reef (iii) Atoll. Australia and in the Philippines.

Fringing Reef: Coral reefs that develop 6. Only a few coral reefs lie outside the Indo- along the continental margins or along the Pacific tropical area, those of Gulf of Mexico islands are called fringing reefs. The seaward and the Caribbean Sea have some reefs. slope is steep and vertical while the landward slope is gentle. Such reefs are found near El Nino and La Nina Rameshwaram in the Gulf of Mannar. Occasionally the fringing reef is separated from El Nino is a warm sub-surface current in the the shore by shallow lagoon known as "Boat Pacific Ocean off the Peruvian coast. El Nino Channel" as found in Madagascar and Red Sea. literally means 'child of the Christ'. It is a Example of fringing reefs: South Florida reef, destructive weather system pushed into action Mehetia Island, Sakau Island in New Hebrides. by the warming of the cold ocean current in the Barrier Reef: They are the largest, most east pacific. El Nino's destructive capacity peaks extensive, highest and widest reefs of all types by late October or November, when it starts to of coral reefs. They are formed off the coastal cool down and is called La-Nina or literally 'The platforms and parallel to them. There is an girl'. El Nino affects the monsoon in India. An El extensive but shallow lagoon between the coastal Nino circulation in the winter suggests a strong land and the barrier reef. Generally barrier reefs walker circulation in the following summer and encircle islands in an irregular and broken ring. consequently a weak monsoon. However The Great Barrier Reef owww.OnlineIAS.comf Australia is the largest scientists are still skeptical about its relation with barrier reef in the world. monsoon. Recently its link with the fire in Indonesia has been subjected to much debate. Atoll: A ring of narrow growing corals of horse shoe shape and crowned with palm trees Ocean currents is called an atoll. It is generally found around an island or in an elliptical form on a submarine The regular movements of water from one platform. There is a lagoon in the middle of a coral ring. They are more common in Pacific part of the ocean to another are called "Ocean Currents". They are mainly caused by the Ocean. The circular ring is broken at few places to difference in density of sea water due to allow the free flow of water. The depth of the lagoon is only a few metres with sand and variations in temperature and salinity. The prevailing winds push them onwards. The limestone debris at the bottom. Example of Atolls: position of the land masses and the shape and Fiji Atoll, Trunt Atoll of W-Carolinas, Suvadivo depth of the ocean basins also have some

www.OnlineIAS.com N. Kalyana Chakravarthy 64 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] influence. Main causes of ocean currents include continuation of South Equatorial Current.

- winds, differences in density owing to 9. Falkland Cold Current: Similar to Labrador variations in temperature and salinity. Ocean cold current, this cold water of Antarctica currents may be cold or warm. moves on along the Argentina coast. It brings icebergs with it. A. Atlantic Ocean Current 10. South Atlantic Drift: It is the continuation 1. North Equatorial Current: Attributed to of easterly deflected Brazilian current NE-Trade winds, it starts from west coast which moves earthward between 45°S to of Africa where upwelling of cold water 60°S under the influence of strong takes place and moves westward between westerlies. A branch of it is diverted along the 5° and 20° N as warm current. A branch west coast of Africa and moves north as of it is diverted into Caribbean Sea as "Benguela Current." "Antilles Current."

11. Benguela Current: This cold current flows 2. South Equatorial Current: Flows south of northward along the west-African coast. If the equator between 0° and 12° latitude in finally joins South Equatorial current. between the coast of Africa and S. America. This warm current is virtually the B. Indian Ocean Currents: continuation of cold Benguela current. Being blocked in the north by the continental 3. Equatorial Counter Current: This warm mass the Indian Ocean represents only the current flows between the two strong southern part of the ocean. The northern part equatorial currents and moves towards the develops a reversal system of currents as per the opposition direction in the east. In the eastern seasonal rhythm of Monsoon. In summer the part it is known as "Guinea Current." North Equatorial current is replaced by SW-

4. Florida Warm Current: It flows from the Monsoon current flowing from west to east and strait of Florida to Cape Hatteras which is throwing branches into the Bay of Bengal and the a continuation of North Equatorial current Arabian Sea. On the northern coast of Africa in the Gulf of Mexico. along Somaliland the upwelling takes place and a cold current develops, known as "Somali 5. Gulf Stream: The warm water of Antilles Current". South Equatorial current flows north and Florida current after joining together of 20ºS between Australia and Africa. After flows as Gulf Stream, off the Cape Hatteras. striking the landmass of Africa it splits into many After it, it is deflected eastward under the branches; the major one turning southward to combined influence of westerlies and the form the "Agulhas Current". rotation of the earth. Mozambique Current: A branch of South 6. North Atlantic Drift: East of Grand Bank, Equatorial Current at 65°E is bifurcated towards the Gulf Stream flows as slow moving North the north of Malagassy Republic and flows Atlantic Drift. It is www.OnlineIAS.comfurther divided into two through the Mozambique Channel known as parts - the northern branch flows in the Mozambique current.

Norwegian Sea and the southern branch West Wind Drift: Under the stress of westerly flows south of Ireland as "Irminger Current"; wind the cold water at 40°S moving in the easterly another branch flows along the coast of direction is known as West Wind Drift. One France and Spain as "Canary Current". Branch of it flows northward along Australia 7. Labrador Cold Current: It flows from Arctic which forms West Australian Cold Current.

Ocean and move southward along the coast West Australian Cold Current: Flowing on of Canada and meets the warm Gulf Stream the west coast of Australia, its gains its water producing famous fog ground along the from west wind drift. Newfoundland as the great fishing ground. C. Pacific Ocean Currents: 8. Brazilian Warm Current: It flows along the S. American coast as the southward The Ocean Currents in the Pacific Ocean

www.OnlineIAS.com N. Kalyana Chakravarthy 65 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] have a pattern similar to that in the Atlantic not much, sea water recedes from the shore. Such Ocean. Due to vast water masses the counter waves constitute a low tide. current has become very stable. Ebb Tide: The tide between a high tide and 1. North Equatorial Current: It flows from a low tide is known as ebb tide. Mexican coast to Philippines between 5N Spring Tide: When the amplitude difference and 10N latitude. It is a warm well of the tide in a day is at maximum, the tide is developed current. called spring tide. It occurs on new moon and full 2. South Equatorial Current: It is also a warm moon days. High tides are very high and low tides current, south of North Equatorial Current. very low on those days.

3. Counter Equatorial Current: This warm Neap Tide: When the amplitude of the tide current is very sable in nature. is minimum. It occurs on the first quarter and last quarter of the moon. High tides are comparatively 4. Kuroshio Warm Current : Similar to Gulf low and low tides comparatively high. stream of Atlantic Ocean, it flows from Formosa to Rique, "Tsushima Current" is Tidal Bores: When a tidal wave meets a its branch which goes to Japan Sea and is tidal river or estuary, a tidal bore is formed. a warm current. Where the outgoing river currents are strong and the tidal river rather shallow and tunnel shaped, 5. Kurile / Oyashio Cold Current: It flows the rapidly rising high water advances up stream southward from the baring strait. Near 50°N like a high vertical wall, known as tidal bore. latitude it meets to Kuroshio Current causing fog. • Bore occurs at river mouths that face the direction of tidal surge and where tidal 6. Californian Cold Current: Similar to range is large. Rivers like Amazon, Canaries current it flows along the west Hooghly, Colorado, Yangtze are coast of N. America. characterized by tidal bores.

7. Peru / Humboldt Cold Current: It flows • Although tides occur twice a day, their along the Peru coast. interval is not exactly 12 hours; actually it is of 12 hours and 25 minutes. This is 8. East Australian Current: It is a warm due to the revolution of the moon and the current along the east Australian coast. rotation of the earth.

9. West Wind Drift: This cold current flows • Generally tides occur twice a day. But from west to east direction between 40°S and Southampton, along the southern coast of 50°S. It is also called as "Roaring Forties". England experiences tides four times a day because the tidal water comes through the Tides English Channel and through the North Sea at different intervals.

The alternative rise www.OnlineIAS.comand fall of the level of the • Tides in the area of the sea, known as Sea, approximately twice a day, caused by the "Gulf Tides" also causes the horizontal gravitational pull of the moon and the Sun is movement of water of the sea known as called tide. The gravitational attraction of the "Tidal Current". moon is twice as powerful as that of the Sun. The moon despite being much smaller in size than the • Monthly tides occur due to revolution of Sun is relatively very close to the earth and is moon and its position at perigee and thus able to attract more than the Sun. apogee.

High Tide: When the intensity of the wave • Equinoctial Spring tides recur at an is great, the waves are of considerable amplitude interval of 6 months, due to revolution and so the sea water comes over the coast to some of the earth around the sun and sun's extent. Such waves constitute a high tide. varying declination.

Low Tide: When the height of the wave is • Yearly tides recur due to revolution of the

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earth and its position at perihelion and 9. The region with maximum tidal power aphelion. potential in India is "Gulf of Cambay".

Importance of tides 10. Dogger Bank is in North Sea.

1. Tides make some of the rivers navigable for 11. The tidal theory of Jeans and Jeffery ocean going vessels e.g., Kolkata, London etc. explains the formation of Earth.

2. Tides clear the sediments brought by rivers 12. Oceanic ridge are found along the diverging and thus retard the process of delta boundary. formation. 13. The tidal producing forces of Sun and Moon 3. Tides are agents of distribution; biologically are in the ratio of 4:9. they distribute and redistribute the plankton and nektons along with coastal 14. The tract of land between two adjacent water which helps in fishing industries. rivers is called "interfluve".

4. The tidal force may be used as the source of 15. The tidal mouth of a river where saltwater meets freshwater is called "Estuary". electricity e.g. In France, Japan, India etc.

16. End of the continental block is marked by Points to remember the seaward limits of continental slope. 1. Waves caused by earthquakes are known as "tsunamis." 17. Maximum thickness of sediments is found over "continental Slope". 2. "Cirrus" and "small cumulus" type of cloud are associated with fair weather. 18. Region of maximum salinity over the Indian coast is the "Gulf of Kutch". 3. A rock layer through which groundwater moves freely is "aquifer". 19. Spring Tides occur when Sun and Moon are either in conjunction or opposition. 4. Lake Knebel in Iceland is a "crater lake". 20. The unit of measurement of flow of a fluid 5. Drizzle is produced generally by "stratus" is "Cusec". or "Strato Cumulus". 21. The busiest ocean route in the world is 6. Sargasso Sea is in "Atlantic" Ocean. "North-Atlantic route".

7. Country having largest deposits of organic 22. OTEC has the maximum power generation phosphates is "Peru". potential in India.

8. Hammerfest, the northernmost ice free port, 23. The average one kg of sea water contains is in "Norway". 345 gram of salts.

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SOIL

Soil may be defined as a thin layer of earth's Soil textures: crust which serves as a natural medium for growth of plants. It is the unconsolidated Soils Types Sand Clay Silt mineral matter that has been subjected to, and Sandy Loam 65% 15% 20% influenced by, genetic and environmental factors-- parent material, climate, organisms and Clay Loam 33% 33.5% 33.5% topography all acting over a period of time. Soil Loam 40% 18% 42% differs from the parent material in the morphological, physical, chemical and biological Silty Clay 10% 45% 45% properties. Also, soils differ among themselves in some or all the properties, depending on the Silt Loam 17% 13% 70% differences in the genetic and environmental Water retention of different soil types: factors. Thus some soils are red, some are black; some are deep and some are shallow; some are Pure sand holds least water while pure clay coarse textured and some are fine-textured. They holds the most. Loam holds the intermediate serve as a reservoir of nutrients and water amount. Sand transmits the water downward for crops, provide mechanical anchorage and most rapidly and the clay most slowly. Sand favourable tilth. The components of soil are reaches its full capacity very rapidly and added mineral matter, organic matter, water and air, water is wasted. Clay-rich loam takes up water the proportions of which vary and which very slowly and if irrigation is too rapid, water together form a system for plant growth; hence will be lost by surface runoff. Sandy soil requires the need to study the soils in perspective. more frequent watering than clay-rich soil. The intermediate loam texture is generally best as Soils are derived from consolidated parent agricultural soil because it drains well and also rocks by the process of weathering followed by has favourable water-retention properties. pedogenesis. Weathering refers to the physical and chemical disintegration and decomposition of rocks which are not under equilibrium under Soil Profile temperature, pressure and moisture conditions on the earth's surface. In the begin- It is a vertical section of soil through all its ning, weathering precedes soil formation, more horizons and extends upto the parent materials. so in hard rocks. In otherwww.OnlineIAS.com words, weathering A study of soil profile is important both from the creates the parent material over which soil for- standpoint of soil formation and development mation takes place. Later, weathering, soil for- (pedology) and crop husbandry (edaphology). In mation and development proceed simulta- deep soils the soil profile may be studied upto one neously. The product of weathering is called re- metre and a quarter and in others upto the parent golith (small particle of rock). Under the influ- material. The layers (horizons) in the soil profile ence of pedogenic processes, it finally develops which vary in thickness may be distinguished into mature soil. from the morphological characteristics which include colour, texture, structure, etc. Factors affecting soil formation other than • O Horizon the regolith are: At the top of the profile is the O horizon. This 1. Climate 2. Vegetation is primarily composed of organic matter. Fresh 3. Relief, 4. Parental materials litter is found at the surface, while at depth all signs of vegetation structure have been 5. Living organism 6. Time destroyed by decomposition. The decomposed

www.OnlineIAS.com N. Kalyana Chakravarthy 68 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] organic matter or humus enriches the soil with This is a zone of illuviation where eluviated materials from the upper horizons are

accumulated. The accumulation of fine material

leads to the creation of a dense layer in the soil. In some soils the B horizon is enriched with

calcium carbonate in the form of nodules or as a

layer. This occurs when Capillary action brings

cations like calcium and sodium dissolved in soil

water upwards where they precipitate from the

water.

Eluviation is significant in humid climates

where ample precipitation exists and a surplus in the water balance occurs. Illuvial layers are

found low in the soil profile. Illuvial zones are

found closer to the surface in semiarid and arid climates where precipitation is scarce.

• C Horizon - Big rocks

The C horizon represents the soil parent

material, either created in situ or transported

into its present location. Beneath the C horizon nutrients, aids soil structure (acts to bind lies Horizon R (Bedrock). The bedrock layer is particles), and enhances soil moisture retention. present in just about every different type of soil • A Horizon (The Top Soil) profile. This layer is made of hard, solid rock, which is eroded and weathered to produce most Beneath the O horizon is the A horizon. The of the soil above it. A horizon marks the beginning of the true mineral soil. In this horizon organic material Soil Classification mixes with inorganic products of weathering. A horizon is typically dark colored due to the Soil Orders: Soils can be subdivided into three presence organic matter. Eluviation, the removal orders known as zonal, intrazonal and azonal. of inorganic and organic substances from a (i) Zonal soils: They are formed under the horizon by leaching, occurs in the A horizon. conditions of good soil drainage through the Eluviation is driven by the downward movement prolonged action of climate and vegetation of soil water. and are by far the most important and • widespread of the three orders. E Horizon

The E horizon generally is a light-colored (ii) Azonal soils: They have no well-defined profile horizon with eluviatiowww.OnlineIAS.comn being the dominant either because they have had insufficient time to process. Leaching or the removal of clay develop or because they are on slopes too steep to allow profile development. particles, organic matter and/or oxides of iron and aluminum is active in this horizon. Under (iii) Intrazonal soils: They are simply those coniferous forests, the E horizon often has a high formed under condition of very poor concentration of quartz giving the horizon an drainage or upon limestone whose ashy-gray appearance. influence is dominant. • B Horizon (Subsoil)

Beneath the E horizon, lies the B horizon.

Order zone Groups Soils Zonal Humid Podzolized soil Podzols.

Brown Podzolic

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Gray Brown Podzol

Red- Yellow Podzol

Latosols A. Reddish- Brown Laterite B. Black & Dark Gray Tropical.

Soil of Forest- A. Chernozem

Grassland transition

Intra-Zonal Semi- arid, Dark coloured A. Prairies Soil (Brunizem Soil).

Sub-humid soil of semi- arid B. Reddish Prairies

of marshes, swamps, B. Meadow Soil (Wiesenboden Soil)

bogs, and flat uplands: C. Alpine Meadow. D. Planosols.

Arid, Halomorphic Soil of A. Saline Soil (Solanchak) Semi-Arid poorly drained Arid B. Alkali Soil (Solonetz)

and coastal regions

Calcimorphic Soils A. Rendzina

Azonal Sub-Humid Lithosols (Mt. Soils) A. Alluvial

Regosols B. Sandy (dry) Major soil groups and their characteristics: 4. Prairies soil: similar to chernozem. But it lacks the excess calcium carbonate of the 1. Podzol: one of the most widespread and most chernozems. Extremely productive. Maize developed soils. Rich in humus, low in fertility, and wheat are the main crops associated deficient in bases like calcium, magnesium, with it. potassium and phosphorous. Closely associated with the sub-arctic climate and the 5. Chestnut soil: it is the zonal soil of mid- cooler parts of the marine west coast climate. latitude grasslands that occurs in drier region. It has considerably low content of 2. Latosols: characteristics of humid tropics. organic materials. Its parent material is Chief characteristics include: generally loess. The chestnut soil occurs in (a) Complete chemical and mechanical south Ukraine, the great plains of the U.S.A. and South African veldts. decomposition of the parent rock.

(b) Silica entirely leachedwww.OnlineIAS.com from the soil. 6. Hydrographic soil: it is associated with marshes, swamps, bogs or poorly drained (c) Complete lack of humus. flat uplands. They are all intra-zonal soils. "Bog" soils are formed under bog vegetation (d) A reddish brown colour given by the in regions of cool continental climate. oxides of iron, aluminium and manganese. 7. Desert soil: It is grey in colour in temperate region and red in hot deserts of tropic. The 3. Chernozem soil: zonal soil in a semi-arid cold desert soil is found in mid-latitude cold climate. Horizon ‘A’ is rich in humus. desert region and lack in humus. It has one of Horizon ‘B’ is rich in bases. Generally the best cotton producing regions of the world. acidic. It is found in Ukraine, central USA, central Africa, South America and 8. Tundra soils: It develops in such regions Australia; it is highly productive for small where summer is short (3 months) and grain crops like wheat, oat, barley etc. winter is long (9 months). Plant growth is

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restricted. Even percolated water is frozen 5. The grey-brown podzolic soil differs from during the winter. No chemical and podzols in that leaching is less intense and biological action takes place for over nine contains more of the important base than months. Wherever frozen ice melts, marshy the podzols.

soil is developed. Canada and the erstwhile 6. The pedogenic regime of “gleization” is U.S.S.R. have this type of soil. characteristic of poorly drained environments under a moist and cool cold climate. Points to remember 7. The dark-coloured soil absorbs more of 1. The “soil profile” refers to the arrangement sun’s heat than the light coloured one.

of the soil into horizons of differing texture, 8. Most matured soils have a layered colour and consistency. arrangement of strata called “horizon”.

2. “Brunizem” soils are also termed as 9. “Podzolisation” commonly occurs in a “prairie” soil. typical regime of coniferous forest regions.

3. “Calcification” is a pedogenic regime of 10. “Leaching” is a process of removal of climate in which evaporation on the minerals in solution from the upper layers average exceeds precipitation. to the lower layers of soils e.g. “Podzol” 4. The deposition of colloids and bases in the type of soils. underlying B horizon is a process known as “illuviation”.

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NETURAL VEGETATION

• Equatorial Evergreen Forest 4. Area: Caribbean Land, SE-Florida, South and South-east Asia, Eastern Brazil coast, 1. These forests are located close to the equa- Madagascar coast, North-east Australian tor- Amazon and Congo basins, Malay- coast. sia, Coastal Burma, Cambodia, Vietnam, Indonesia, New Guinea etc. - where the • Tropical Monsoon Forest rainfall is heavy. Example of trees - Ebony, 1. They are located in Burma, Thailand, Mahogany, Rosewood, Rubber etc. Cambodia, Laos, North Vietnam, parts

of India, North Australia etc. Species - 2. Consists of tall, closely set trees. Their Teak, Rubber, Bamboo, Mango, Sal, San- crown form continuous canopy of foliage. dalwood, Acacia, Eucalyptus etc. 3. Trees are smooth-barked and un- branched in the lower two-third part. 2. More open tree growth than Equatorial and Tropical Rain Forests. 4. Leaves are large and evergreen so called 3. Less competition among trees for light "Broadleaf Evergreen Forest". so greater development of vegetation in 5. Thick, woody lianas are common with lower layers.

tendrils or suckers to climb. 4. Trees trunks are massive with rich and 6. Epiphytes are numerous and they in- rough bark.

clude fern, orchid, mosses and lichens. 5. Most of the trees are deciduous, and 7. Trees are not found in a single stand. sheds their leaves in long dry season.

Thus considerable labour is involved in 6. Teakwood trees are representative ex- economic activities. ample of monsoon forest.

8. Due to high temperature there is a rapid 7. Clumps of bamboo are the important consumption of dead plant matters by part of vegetation. bacterial action which results in the absence of humus on the soil-surface. • Temperate Evergreen Forests

9. In the absence www.OnlineIAS.comof cold and dry season 1. Located chiefly on the eastern sides of plant growth goes on continuously landmasses in warm temperate latitudes throughout the year. Individual species - South China, South Japan, Southeast have their own seasons of leaf-sheding. Australia, South Brazil etc. Examples of trees - Evergreen Oak, Magnolia (China • Tropical Rain Forest & U.S.A.), Camphor and Bamboo

(China), Eucalyptus (Australia) etc. 1. Quite similar in structure to the equato- rial variety and extends in the tropical gone of 2. Unlike Equatorial and Tropical Rain 10° to 25°N along the wind- ward coast forest it has relatively few species of trees. of trade winds. 3. Leaves tend to be smaller and more 2. The trade wind littoral climate in which the leathery; the leaves canopy is also less tropical rainforest thrives has a short dry dense. season. 4. Have a well developed lower stratum of 3. Epiphytes are abundant because of con- vegetation. Lianas and epiphytes are tinued exposure to humid air. abundant.

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5. The annual range of temperature is small high latitudes and on high mountains. or moderate and rainfall is abundant and well distributed throughout the year. 2. This is a forest of evergreen, cone-bear- ing trees.

• Mediterranean Forest 3. Examples of trees: Spruce, Blue Pine, 1. This type occurs on the Western sides of land Hammock, Larch. masses in the warm temperate lati- tudes: 4. These conifers are extremely important low lands around the Mediterranean Sea, for their soft wood required for the pa- South-West Australia, Southwest Af- rica, per, match and synthetic fibre industry, Central Chile and Central California. found mainly in Northern Canada and Examples of trees: Evergreen Oak, Olive, Northern Eurasia. Grape, Eucalyptus, Redwood etc.

5. The trees have straight trunk, conical 2. Consists of low trees with small, hard shape with short branches and small leathery leaves. needlelike leaves. 3. Today large areas consist of dense scrub, 6. In N. America, Europe and western Si- locally known as "Maquis". beria it is known as "Boreal Forest." 4. In the Californian coast it is known as 7. In Canada it bears the hygrophytic veg- "Chaparral" and in Australia as etation as forming a bog succession and "Sclerophyll Forest". leading to large thick peat accumulation • Cool Temperate Forest known as "Muskeg".

1. Deciduous trees predominant. • Tropical Grasslands

2. Regions include - West and Central Eu- 1. Tropical grasslands are located mainly rope, Eastern U.S.A., North China, in the continental regions of tropical North Japan New Zealand etc. Examples latitudes where rain occurs in the hot of tree - Maple, Birch, Ash, Alm, Oak, season which lasts for about 5 months.

Beech, Chestnut, Walnut etc. 2. Important regions - north and south of 3. Dominated by tall, broadleaf trees. Zaire Basin, West Africa and east Af- rica plateau, parts of Brazil, Guiana 4. Trees provide dense canopy in summer but Highlands and part of Deccan plateau shed their leaves completely in the winter. in India.

5. It is almost entirely limited to the mid- 3. These are known by different names in latitude landmass of the N-Hemisphere. different regions:

6. This forest represents a response to a Campos - Brazil continental climatwww.OnlineIAS.come in which rainfall is adequate throughout the growth season. Llanos - Guiana Highlands

7. Rainfall in greater in summer months Savanna - Africa and Australia and the soil water demand is high. • Temperate Grasslands • Temperate Mixed Forests: 1. These grasslands are almost treeless- 1. Between temperate deciduous and tem- thus contrasting with tropical grass- perate coniferous forests. lands.

2. Trees: Aspen, Birch, Alder etc. 2. They are best developed in continental interiors of temperate latitudes. • Coniferous Forests or Taiga 3. Important temperate grasslands of the 1. This type of forest is most extensive in world include:

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Steppe - Eurasia 350 latitudes.

Prairie - North America 2. Aridity and a great annual temperature Pampas- Argentina with extremes of winter cold mark the Veldt- South Africa region. Downs- Australia • Tropical Desert 3. In North America these deserts are found in basins surrounded by the 1. These are mostly situated between 15º - Rockies. 30º N and S on the western sides of land masses. 4. In South America the Patagonia desert lying to the east of the Andes is a typi- 2. The chief regions are: Sahara (North Africa), cal example. Arabia, parts of Iran, Iraq, Syria, Jordan and Israel, parts of Pakistan, Central Australia, • Tundra Namib Desert (South West Africa), Atacama 1. This type of vegetation is chiefly con- (coastal Peru and North Chile). fined to the northern hemisphere, fring- 3. The most common plants are cacti, thorn ing the Arctic “ocean in the continents bushes and coarse grasses. of Eurasia, North America and Greenland Coast. • Mid-latitude Deserts 2. Important vegetation includes - mosses, 1. These are situated in the interior of Asia lichens end a few small shrubs. and North America between 300 and

Sn Type of Forests Important Areas Main Characteristics Important Species

A Evergreen 1. Equatorial Rain Amazon basin, Zaire basin. Broad leaves; evergreen; Mahogany, ebony, Forests Forests are called Selvas in growth never stops; Tall trees; Rose wood, Iron wood, Brazil. Indonesia, Andaman- very dense, darkness at the gr- Rubber, mangrove Nicobar, Borneo, etc. ound, hard wood. Many kinds along the coasts. of trees in a small piece of land.

Economically not developed. 2. Mid Latitude South China, S.E., USA and Hard wood, broad leaves, mixed Oak, Eucalyptus, Wattle Evergreen Forests Soutwww.OnlineIAS.comh Brazil. East coast S. trees, most of forests have been have economic value. Africa & S.E. Australia cleared for agriculture. 3. Mediterranean Western margins of Continents Moderate rainfall in winter, Cork, Oak, Olive, Forests in the subtropical belt. Areas summers are dry. Plants have Chestnut and Citrus surrounding Mediterranean spiny, waxy or small leaves. fruits.

Sea, Central Chile, California, Thick bark and deep roots can

S.Australia. withstand long dry summer. 4. Coniferous Continuous belt between Growing season limited; Trees Pine, Hemlock, Cedar,

Forests 55°-70°N latitudes. Siberia, are tall, evergreen and conical Fir & Spruce; Wood is

northern Europe and Canada, in shape. Needle shaped leaves. used for making pulp high mountains. Soft wood. Highly exploited. and paper.

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B. Deciduous

5. Tropical Decidu- Monsoon regions of Asia, part Trees shed their leaves in the Teak, Sal, mango,

ous Forests parts of Central America, dry season; Less dense; broad Sandal wood, bamboo,

Brazil, Northern Australia. leaves; economically valuable.

6. Mid latitude W. Europe, NE China, NE Trees shed their leaves in winter. Beach, Elm, Oak,

Deciduous Forests U.S.A., Japan, S. Chile and Rapid plant growth in summers. Poplar and Chestnut

New Zealand..

C. Grasslands

7. Tropical Either sides of Congo and Long and coarse grass, with Savanna or Elephant

Grasslands Amazon valleys. few small trees. Land of big grass long up to 9

games. feet.

8. Mid-latitude Temperate continental Low rainfall in summer helps Soft and nutritive grass

Grasslands interior. Steppes (Europe), togrow small grass well developed. for animals, very fertile

Prairies(N.America),Pampas Commercial herdingispracticed. soil for wheat growing.

(S. America), Veld (S.Africa), Famous for wheat (Bread Bask- Extensive farming.

Downs (Australia) ets of the world).

D. Desert

9. Hot Desert Sahara, Kalahari, Thar, Arab, West Thorny trees like ‘Babul’, Acacia, Cactus, Acacia, thorny

Thorny Forests Australia, Atacama and Mexico. Date, Palm, Thorny bushes. bushes, thorny grass etc

10. Tundra Type North polar areas in Eurasia Very long winter with snow clad Patches of mosses,

Vegetation and North America area, very short summer. lichens, shrubs.

Order Sub-order Associated Climate Forest Biome Equatorial & Tropical Rainforest Wet Equatorial

Monsoon & Trade wind Littoral

Montanewww.OnlineIAS.com Forest Highland Wet Equatorial

Highland Monsoon & Trade wind belt

Monsoon Forest Wet Dry Tropical

Dry Tropical, Semi-arid

Broad leaf Evergreen/ Laurel Forest Moist Sub-tropical Marine west coast Mid-latitude Deciduous Forest Marine west coast

Moist continental Needle-leaf Forest Marine west coast (N. America) Moist continental (N. America) Boreal Forest

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Sclerophyll Forest Mediterranean Savanna Biome Savanna Woodland Wet-dry-Tropical Thorn tree tall grass – Savanna Dry-tropical, semi-arid, Semi desert Dry-subtropical, Semi-arid Semi-desert Grassland Biome Prairie (Tall grass) Moist Sub-tropical Moist Continental Steppe (Short grass) Dry Mid-latitude, Semi-arid Moist Continental, Sub-humid Desert Biome Thorn tree-Semi-desert Dry Tropical Semi-desert, Desert Dry Subtropical, Semi desert, Desert Semi-desert Dry Tropical, Semi-desert, Desert Dry Subtropical, Semi desert, Desert Mid Latitude, Semi desert, Desert Dry Desert Dry-Tropical Desert Dry sub-tropical Desert Dry Mid-latitude Desert Tundra Biome Arctic Tundra Tundra Alpine Tundra Highland climate, Alpine zone

World Classification of Vegetation 2. The “Mediterranean” type of vegetation oc- curs in central California and central Chile. Trophophyte: Tropical deciduous vegetation and grass. 3. The “desert type” of vegetation is found in

coastal Peru and southern California. Hygrophyte: Humid areas i.e. Equatorial hot wet forests. 4. Alternate wet and dry seasons cause the growth of distinctive vegetation called Hydrophyte: Vegetation of watery areas. “Tropical Savannah”.

Xerophyte: Tropicalwww.OnlineIAS.com Deciduous desert 5. The tropical evergreen forest consists of the vegetation. trees like lions, broad-leaved evergreens, flowering and fruit plants and their leaves fall Mesophyte: Temperate areas vegetation. all at the same time.

Cryophyte: Vegetation of Tundra and 6. The occurrence of wet winter and dry sum- cold regions. mer is unique among Mediterranean climate Halophyte: Salty areas vegetation types and results in distinctive natural veg- (Mangrove). etation known as “Sclerophyll forest”.

Lithophyte: Vegetation of Rocks & Stones. 7. In tropical monsoon type of climate, the rainfall is seasonal and generally occurs in Points to remember summer and may be as high as 300 cm in

favourable location. 1. Maple, Walnut, Mulberry, Magnolia and Camphor trees are found in temperate 8. In “Tropical Savanna” climate, the rainfall evergreen forests.

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is 160 cm and temperature is about 23°c. 11. The “highlands type of climate” is found in the Mountainous region of Himalayas, Ti- bet 9. The “Steppe” are the areas of compara- plateau, Rockies, Andes and Alps, which have tively lower temperature and slightly more high diurnal range of “temperature”. precipitation. 12. The “alpine” forests are found from “2880 10. The “China-type” climate is a type of humid to 3600” m height on Himalayas. “mesothermal climate” and characterized by warm summer and cool-winter. Its average tem- perature is 19°c and annual rainfall is “120 cm”.

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POPULATION

Human geography embraces the study of 7. Mineral and Energy Resources: Population human race, the growth of human numbers, the map of W. Europe is more or less identical movements and density of population, etc. Thus to distribution of coalfields and other human geography is a science which studies the industries. S. African Rand, Appalachian relationship between man and environment. Coalfield, Donetz Basin, W-Australia also show its effects. Factors Influencing Population Distribution 8. Economic Factor: Density of population is 1. Accessibility: Man was unable to reach directly proportional to technological and inaccessible areas of forest, islands, economic advancement. Migration of mountains for a long time, so such areas have Indian labourers to Mauritius, Trinidad and low density as in the Amazon basin, S. Fiji under colonial rule shows this pattern. American Plateaus, etc. 9. Political Factors: Unlike communist countries 2. Relief: Steep gradients, high mountains, in the western world various inducements rugged-terrain restrict settlement because may be offered to encourage migration to of hindrances in movement. Similarly rivers new towns. Mass migration of Asian from may exert either a positive or negative Uganda in 1972 is another example. effects. Most attract settlement but some 10. Historical Factor: Relatively recent settlement are liable to flooding, change of coarse and of Australia is the basic reason for its low so hinder settlements. density of 2. While high density of India is 3. Altitude and Latitude: There are very few liable to be explained in terms of its long settlements above 5500 m in Andes and history of civilization and occupancy.

Himalayas. 'La Paz' (Bolivian Capital) is at I. High Density zone the height of 3640 m. Low latitude high plateau areas provide positive advantage. 1. East Asia including China, Japan, Korea, Philippines, etc. 4. Climate: Extreme heat, cold, humidity and aridity deter settlement. Success of crops 2. S.E. Asia including Burma, Malaysia, also depends on climate. But no specific Indonesia, Thailand, Cambodia, climate is optimum for settlement as obvious Vietnam. from the fact that twwww.OnlineIAS.como of the world primary concentration of population lie in middle 3. S.Asia including India, Srilanka, Bangladesh, Bhutan, Nepal, Pakistan etc. latitude and the third is located in the tropics. For example Java Island and 4. N.W. Europe: including European Amazon Basin have the same climate but former USSR. population density of Java is over 500 whereas Amazon basin has less than 1. 5. N.E. Coastal N. America

5. Soil: Deltaic and alluvial soils attract settlement • The first three concentration zones while laterites and podzols repel. All ancient belong to Monsoonal regions having civilizations evolved in alluvial soil regions. about 57% of the world population. Higher density of Jawa as compared to China and India alone constitute 38% Sumatra is also due to soil fertility. of world population. East Asia has 25% and S.Asia has 23% of World 6. Natural Vegetation: It may also exert Population. positive as well as negative effects on • Monsoonal regions are characterized settlement. by vast fertile land, favourable

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climate for agriculture, perennial 5. High altitude plateau like Tibet rivers, paddy farming and historical (density of below 3), Bolivia.

inertia of human settlement and all 6. Mountains with altitude above 5000 these favour greater concentration. ft.

• Western Europe and NE N. America 7. High latitude regions like Alaska, N. have very high population density Canada, Greenland, Siberia (density due to tremendous development of of about 1). secondary and tertiary industries. Demographic Transition Theory • Although having almost infertile Formulated by Frank Notestein in 1953, the lands small countries like theory of Demographic Transition makes an Netherlands, Belgium, Luxemberg attempt to document the experience of have very high density because of developing countries as affected by the present- high industrial development and day economic growth. 'Demographic Transition' other non-primary activities like is described as the passage through which fisheries and forestry. countries move from high birth and death rates to II. Medium Density Zone low ones. This has been the experience of countries going through a process of modernizing • The density of this zone is between 50 economic and social development. and 70. Their zone contains 5% of the world population. Stages of Demographic Transition

1. The first stage is characterized by high birth • It includes most geographical regions of and death rates. High death rates in such a Savanna land, mid-latitude regions and society could be due to chronic malnutrition, the plateau regions of Equatorial and famines and epidemics, inadequate Monsoonal condition. medicinal and health services and poor living • Most of the countries in this region have condition. High birth rates are influenced entered into the 2nd phase of by the socio-cultural system (i.e. illiteracy, demographic transition, i.e. witnessing early marriage, traditional values, religious population explosion. beliefs, demand for family labour, etc.).

• It includes Mediterranean coastal parts 2. In stage two, that of a developing country, of Morocco, Algeria, Tunisia in N. the death rates drop rapidly due to Africa, Mediterranean coast of Asia, improvements in food supply and sanitation, Plains of Tigris and Euphrates, Eastern which increase life spans and reduce disease. Brazil, S.E. Australia, Californian These changes usually come about due to Region, Coastal Argentina, Venezuela improvements in farming techniques, access and Chile, South Africa etc. to technology, basic healthcare, and education. Without a corresponding fall in III. Low Density Zonewww.OnlineIAS.com birth rates this produces an imbalance, and the

countries in this stage experience a large • It includes regions having population density below 50. It includes about 55% increase in population. geographical area of the world. • They are the regions of invariable geographical condition or the regions of extremely low density, e.g. 1. Dense forest like Amazon and Zaire basin. 2. Dense forest like Taiga

3. Cold deserts like Central Asiatic, Patagonia.

4. Hot deserts like Sahara (density of about 1), Australian desert.

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3. In stage three, birth rates fall due to access 1975 AD 4 billion to contraception, increases in wages, urbanization, a reduction in subsistence 1987 AD 5 billion

agriculture, an increase in the status and 2000AD 6 billion education of women, a reduction in the value of children's work, an increase in 2025AD 8.5 billion (estimated) parental investment in the education of children and other social changes. 2050AD 10 billion (estimated)

Population growth begins to level off. Races of the World 4. During stage four there are both low birth (a) Caucasoid: The Caucasoids are numerically rates and low death rates. Birth rates may one of the largest groups and it includes not drop to well below replacement level as has only white Europeans and people of happened in countries like Germany, Italy European origin living elsewhere, but also and Japan, leading to a shrinking population, Arabs and most of the people of the Indian a threat to many industries that rely on sub-continent. It accounts for 33% of the population growth. As the large group born world population. Caucasoids are also during stage two ages, it creates an economic divided into Nordic (Northern Europe), burden on the shrinking working population. Alpine (central Europe) and Mediterranean Death rates may remain consistently low or people (Arabs, Jews and People of Indian increase slightly due to increases in lifestyle sub-continent). diseases due to low exercise levels and high obesity and an aging population in (b) Mongoloids: Mongoloids are represented by developed countries. the Chinese. Amerinds (native American

Growth Rate of Developing Countries Indians) are perhaps an early offshoot while the Polynesians are a sub-group of the 1. Countries of Explosion: Most of the Islamic Mongoloids with a great deal of racial countries, Latin America, S. Africa, S.E- intermixture. They constitute 43% of the world Asian countries. It has very high birth rate population. over 30% and low death rate of 15%, so natural increase is very high. (c) Negroids: The Negroids are represented by the African people. 2. Countries of Potential Explosion: (d) Australoids: Mostly tribal people are Central African & some S.E Asian represented by these races. countries like Cambodia, Laos, Vietnam. At present both high birth rate and high (e) Hottentots and Bushmen: Africa tribe of death rate over 40%. But in the near West coast and Atacama desert. future death rate will go down hence www.OnlineIAS.comPopulation Terms the population explosion.

Birth Rate: Number of the live births per 3. Countries of Managed Population: They year per 1,000 of the population. have successfully managed the growth rate like China (1.2%), Jamaica (1.4%), S. Africa Death Rate: Number of deaths per year per (0.8%) and El-Salvador (1.2%). 1,000 of the population.

World Population Growth Infant Mortality: Number of deaths of children below 1 year of age per 1,000 of the population. 1 AD 0.25 billion Life Expectancy: The average age at which 1650 AD 0.50 billion people die. It does not mean the age at which most people die. 1820 AD 1 billion Migration: Migration is broadly defined as 1930 AD 2 billion permanent or semi-permanent shifting of residence.

1960 AD 3 billion

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Natural Increase: Excess of births over Maori New Zealand deaths per 1,000 of population. This does not include increase in population due to Masai East Africa immigration. Mbuti North Equatorial region Net Reproduction Ratio: Rate at which Papuans New Guinea women are replaced by daughters who will have children. Poonan Borneo

Optimum Population: A country is said to Pygmies Congo (Zaire) Basin have optimum population when the number of people is in balance with the available resources. Red Indians North America

Regional Variation in Growth Samoyeds Asiatic Tundra

World growth rate : 1.7% Tartars Siberia Africa : 3.0% Tawa Near Equator Latin America : 2.2% Veddas Sri Lanka Asia : 1.7% Yakut Tundra region Former USSR : 1.0% Yukaghirs East Siberia

N. America : 0.9% Points to remember Europe : 0.3% 1. 'Life expectancy' refers to the average age Oceania : 1.5% at which people die; it is 62 years in India, 80 years in Japan and 77 years in Britain. Developing Countries : 2.0% 2. "Jarawas" are inhabitants of Little Developed countries : 0.6% Andaman.

3. "Gauchos" are nomads of the Pampas or Tribes of World Uruguay and Argentina.

Aborigines Earliest people of Australia 4. "Eskimos"are the group of people known as Mongoloid. Bantus Central and Southern Africa Bedouins Nomadic tribe in Africa and 5. The Nilotic and Hamitic people of eastern South West Asia Africa belong to the Negroid group.

Berbers Algeria, Morocco, Tunisia. 6. North-West Europe has the highest density of www.OnlineIAS.compopulation. Bindibu Western Australia 7. "Kikuyu" are the group of people of the Bushman South west-Africa, Kalahari Desert Kenya region. Eskimo Tundra region in Canada and Greenland 8. "Masai" is the aborigines of tropical grassland of east Africa. Finns Tundra of Europe 9. "Bushmen" is the aborigines of Kalahari Gaucho Uruguay, Argentina Desert of Africa especially living in Namibia, Botswana and Angola. Hamits North-West Africa 10. "Bedouins" are the pastoral nomadic tribe Kirghiz Steppes of Asia in Arabia who depends upon camel Kikuyu Kenya breeding and roam in search of fodder.

Lapps Tundra of Europe 11. The "working age group" or "population" is

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constituted by the people of "15 to 59" years. 14. In terms of the number of speakers "Hindi" occupies "fourth" place in the world. 12. The population below the 13 years of age is designated as young and over 60 years as "old". 15. The highest density of urban population in a descending order; Singapore (100%), 13. Five largest linguistic group in descending Belgium (96.8%), U.K. (88.2%) and orders in India: Hindi, Bengali, Telugu, Netherlands (70.0%). Marathi and Tamil which constitute 40.42%, 8.30%, 7.87%, 7.45% and 6.32% respectively.

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HUMAN SETTLEMENT

The functional typology of human settle- Settlements can also be classified on the ments is shaped, among others, by their politi- basis of shape and pattern into: cal? administrative function. Its distinctive place 1. Compact settlements:- is determined by subjective factors, such as the political administrative decisions, which have i. In these settlement houses are built very changed the course of some settlements to the close to each other. benefit of others, or reverted them from their ii. Such settlements are found in river val- normal, natural evolution. That means outside leys and fertile plains. involvement in space organization to the detri- ment of self?organization, the latter being the iii. The people are closely tied and share outcome of the permanent tendency of territo- common occupations. rial systems to rebalance from exogenous 2. Dispersed settlements:- factors?induced dysfunctions. Settlements are classified on the basis of size i. In these settlements houses are built far apart from each other. and function into URBAN and RURAL. 1. Urban settlements: ii. These settlements consist of one or two houses and cultural feature such as a i. These types of settlement are nodal in church or a temple binds the settlement character and have secondary and ter- together. tiary activities. iii. Such settlements are found over hills, pla- ii. The chief occupation of the people of ur- teau and highlands.

ban areas is non-agricultural i.e. indus- Rural Settlements try, trade and services. Rural Settlements: Rural settlements are most iii. The major function of an urban area are closely and directly related to land. They are domi- trades and commerce, transport and nated by primary activities such as agriculture, ani- communication, mining and manufac- mal husbandry, fishing etc. The settlements size is turing, defence, administration, cultural relatively small. Types of the settlement are deter- and recreational activities. www.OnlineIAS.commined by the extent of the built-up area and inter- iv. Population density is high and the settle- house distance. The three factors are: ment size is large. • Physical factors - 2. Rural settlements: a. Nature of terrain:- Dispersed type of i. These settlements are chiefly concerned settlements is found in remote jungles, with primary activities such as agricul- small hills of Himachal Pradesh. Compact ture, mining, fishing, forestry etc. settlements are found in highly produc- tive alluvial plains of Punjab. ii. Most of the people of rural settlement are engaged in agricultural work. b. Altitude:- Dispersed settlements are found in hills of Meghalaya and clustered iii. The major function of rural settlement is and semi-clustered settlements are found agriculture and each settlement special- in Gujarat plains. izes in various activities. c. Climate:- due to frequent droughts settle- iv. Population density is small and the settle- ment may become hamleted. ment size is small.

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d. Availability of water:- Scarcity of water settle on the outer flanks of the village. in Rajasthan has resulted in development e. Such settlements are found in Gujarat of compact settlements. plain and parts of Rajasthan. • Cultural and ethnic factors - 3. Hamleted settlement: -

a. Caste and tribal structure:- due to eth- nic a. When a large settlement gets fragmented factors settlement may become frag- into several smaller units physically sepa- mented and Hamleted e.g. Chhattisgarh. rated from each other but bears a com- b. Religion:- people of same religion prefer mon name it forms hamleted settlement. to live together making a settlement large b. It occurs due to social and ethnic factors. or small. c. These small units of settlements are • Security factors - known as panna, para, palli, nagla, dhani a. Defence from invasions and Wild ani- etc.

mals:- due to defence from dacoits, wild d. Such settlements are found in Ganga animals or fear settlements may cluster plains, lower valleys of Himalayas. and form compact settlements. 4. Dispersed settlement: - On the basis of the type of rural settle- ments found in India are: a. When a settlement has a few isolated huts it is called dispersed settlement. 1. Clustered, agglomerated and nucleated settlement: - b. These types of settlements are found in remote jungles, small hills with a few a. In this type of settlement the built-up area farms and pastures on the slope. is compact and inter-house distance is small. c. It results from extremely fragmented and small resource support. b. In this type of village the general living area is distinct and separatedfrom the d. They are found in Meghalaya, surrounding farms. Uttaranchal, Himachal Pradesh and Kerala. c. Such settlements are found in highly pro- ductive alluvial plains (Punjab), in the On the basis of forms or shapes of the settle- valleys of Shiwaliks (Deheradun) and in ments: north eastern states. These may be a number of geometrical forms and shapes such as: d. Such settlements are also formed due to security and defence reasons (e.g. a. Linear Pattern: It is commonly found along Madhya Pradesh) or scarcity of water or main roads, railways, streams, etc. It may cultivable land (Rajasthan). have a single row of houses arranged along www.OnlineIAS.comthe main artery. For example rural settle- 2. Semi-clustered settlements: - ments found along the sea coast, river val-

ley, mountain ranges etc. a. In this type of settlement the built-up area is less compact as compared to the clus- b. Rectangular Pattern: This is a very common tered settlement. type which develops around the rectangular

shape of agricultural fields as it is common to b. It may result from segregation or frag- find a system of land measurement based on mentation of a large compact village. square units. Village paths and cart tracks also c. Some sections of a village society choose confirm to the rectangular field patterns and or is forced to live a little away from the run through the village in north-south and main cluster or village. east-west directions. Accessibility to farms and fields and connectivity to other settlements lead d. The land-owning and dominant commu- to rectangular shape of settlements. The settle- nity occupies the central part of the main ments of coastal Maharashtra and Andhra village, whereas people of lower status of

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Pradesh and either side of Aravali hills, etc. riverside, a road, an orchard, a well or even may be cited for examples. a place of worship. Such patterns are com- mon in the delta region where the dwellings c. Square Pattern: This is basically a varient simply follow the fan shaped profile of the of rectangular type. Such a pattern is asso- delta as in the case of Mahanadi, Godavari, ciated with villages lying at the crossing of Krishna, Cauvery, etc. Such patterns are also cart tracks or nroads and also related to common in the Himalyan foothills. features restricting the extension of the vil- lage outside a square space. These features Major problem of rural settlements are: may include an old boundary wall, thick orchards, a road or a pond. i. Rural settlements in the developing coun- tries have poor infrastructure facilities. d. Circular Pattern: In the upper Doab and Trans - Yamuna districts, Malwa region, ii. Supply of water to rural settlements in Punjab and Gujarat, large villages are char- developing countries is not adequate. acterized by a very high degree of com- People in villages, particularly in mountain- pactness. The outer walls of dwellings ad- ous and arid areas have to walk long dis- tances to fetch drinking water. join each other and present a continuous front so that when viewed from outside, iii. Water borne diseases such as cholera and jaun- the villages look like a walled and fortified dice are common problem because of lack of safe enclosure pierced by a few openings. The drinking water and unhygienic conditions. round form was a natural outcome of maximum aggregation for the purpose of iv. Villages are adversely affected by the con- defence during the past. ditions of drought and flood. This in turn affects the crop cultivation. e. Radial Pattern: In this type, a number of streets converge on one centre which may v. The absence of toilet and garbage disposal be a source of water (pond, well), a temple facilities cause health related problems.

or mosque, a centre of commercial activity vi. The houses made up of mud, wood and thatch or simply an open space. Thus, the streets get damaged during heavy rains and floods. seem to be radiating from a common cen- tre. Examples are settlements near vii. Most houses have no proper ventilation. Gurushikar, Mount Abu in Rajasthan, Vindhyachal in Uttar Pradesh, etc. viii.Unmetalled roads and lack of modern com- munication network causes difficulties in f. Checker Board Pattern: This is a type of providing emergency services during floods. settlement found generally at the junction of two roads. The village streets meet each ix. It is also difficult to provide adequate health other at an angle or are parllel to each other. and educational infrastructure for large This is because of the tendency to align the rural population. The problem is particu- dwellings along cardinal axes. This pattern is larly serious where houses are scattered common in the northernwww.OnlineIAS.com plains. over a large area. g. Elongated Pattern: Such settlement occurs as Urban Settlements a result of elongation of the rectangular pat- tern due to influence of site features. For in- stance, According to the census of India urban ar- in the Ganga plains, in areas liable to eas are those which satisfy the conditions given below. inundation, the rectangular pattern becomes unusually elongated along the high ground. (a) All places with a municipality corporation, Even otherwise the advantage offered by riv- cantonment board or notified town area erside location forces such a pattern. committee etc. h. Fan Shaped Pattern: This is seen where some (b) All other places which satisfy the follow- focal points or line is situated at one end of ing criteria: the village. A focal object may be a tank a

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(i) a minimum population of 5000 4. Industrial Towns:- Mining and manufactur- ing regions. Dhanbad and Khetri are ex- (ii) at least 75 percent of male working amples of mining towns. Towns which have population engaged in non-agricultural developed due to setting up of industries such sector, and as Jameshdpur are called industrial towns.

(iii) a density of population of at least 4,000 5. Trading and Commercial Towns:- Many persons per square kilometer. old towns were famous as trade centres such Therefore, there are two broad groups of as Lahore in Pakistan, Baghdad in Iraq and town or urban settlement. The places which sat- Agra in India. Some towns have developed isfy the conditions mentioned in category (a) are as transport towns such as Rotterdam in known as statutory town and the conditions men- the Netherlands, Aden in Yemen and tioned in category (b) are known as census towns. Mumbai in India are port towns.

Urban agglomeration may consist of any one Classification on th e basis of size: of the three combinations given below: Depending on the size and the services avail- (i) a town and its adjoining urban outgrowth; able and functions rendered, urban centres are

(ii) two or more contiguous towns with or designated as town, city, million city, conurbation, and megalopolis. without their outgrowths; and i. Town: Population size in town is higher (iii) a city and one or more adjoining towns than the village. Functions such as, manu- with their outgrowths together forming facturing, retail and wholesale trade, and contiguous streatch. professional services exist in towns.

Examples of urban outgrowths are univer- ii. City: A city may be regarded as a leading sity campus, cantonment area, port area-seaport town. Cities are much larger than towns and air port, railway colonies, etc. and have a greater number of economic

functions. They tend to have transport ter- Functional Classification of urban settlements minals, major financial institutions and This is the most popular and widely accepted regional administrative offices. When the classification of urban places in India as well as in population crosses the one million mark it other parts of the world. is designated as a million city.

The cities are divided as: iii. Conurbation: The term conurbation was

1. Administrative Towns:- National capitals, coined by Patrick Geddes in 1915 and ap- which have headquarters of the adminis- plied to a large area of urban development trative offices of Central Government, are that resulted from the merging of originally called administrative towns, such as new separate towns or cities. Greater London, Delhi, Canberra, Moscow, and Washington. Greater Mumbai, Manchester, Chicago and www.OnlineIAS.comTokyo are examples. 2. Defence Towns:- Centres of military ac- tivities are known as defence towns. They iv. Megalopolis: This Greek word meaning are of three types: Fort towns, Garrison "great city", was popularised by Jean towns and Naval bases. Jodhpur is a fort Gottman (1957) and signifies 'super- metro- town; Mhow is a garrison town; and Kochi politan' region extending, as union of is a naval base. conurbations. The urban landscape stretch- ing from Boston in the north to south of 3. Cultural Towns:- towns famous for reli- Washington in U.S.A. is the best known ex- gious, educational or recreational functions ample of a megalopolis. are called cultural towns. Places of pilgrim- Problems in urban settlements: age, such as Jerusalem, Mecca, Jagannath Puri and Varanasi etc. are considered as The town and cities grow in size and num- religious towns. There are also recreational ber as the urban population expands. The rapid towns such as Las Vegas in the USA.

www.OnlineIAS.com N. Kalyana Chakravarthy 86 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] rate of Urbanisation in developed and devel- squatter settlements instead of removing them oping countries brings a host of urban prob- by providing piped water and sanitation. lems due to a large increase in the number of (c) Control the rural urban migration, it can urban dwellers. reduce the overcrowding in the city

The problems are: (d) increase water supply by building more 1. Housing- lack of house and can't afford of reservoirs. proper housing which leads to development of squatter settlement. (e) more treatment plants should be built and old rusty pipes must be replaced to increase 2. Water supply- shortage of water supply water quality. due to the demand of water supply and poor piping system. (f) educate the public in the virtues of water conservation. 3. Transport- too many cars in major cities. (g) to ease congestion in the developed countries Poor public transport system road and railways network have to extended.

4. Pollution- domestic and industrial waste (h) Build extensive expressways and wider contribute to land pollution in urban areas. roads to ensure smooth flow of traffic. Some steps that can be taken to overcome these problems are: (I) Encourage to use public transport to re- duce traffic congestion such as MRT. (a) Provide low cost housing to relocate slum dwellers and squatter. (j) Increase awareness of health, hygiene and

ills of pollutions. (b) Improve the living condition of slum and

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AGRICULTURE

burnt nutrients are returned to the soil. On the Different Agricultural types interval few years the process is repeated and (1) On the basis of supply of land: Intensive this a cycle is formed in the long run. agriculture and Extensive agriculture Different local names of shifting Cultivation:

• Intensive method is practiced where the Ladang Malaysia supply of land is limited and density of population is high. China, Japan, India, Chengin Philippines UK, Holland, Germany and Belgium practice this method. Milpa Central America & Mexico

• Extensive method is practiced in sparsely Rocha Brazil populated area - where per man land Masole Zaire & Central Africa area is higher and where there is scope for bringing additional land under culti- Jhum N.E. Indie vation e.g. USA, Russia, Australia, Ar- gentina and Brazil. Ray Vietnam & Laos

(2) On the basis of supply of moisture: Hu- Fang Equatorial African Countries mid farming, Irrigation farming and Dry Logan West Africa farming. Conuco Venezuela • Humid farming is practiced where there is no dearth of rainwater for the Tongya Myanmar production of crops. Problems of water Chenna Sri Lanka logging and drainage and soil erosion are present in the heavy rainfall areas. Tamarai Thailand

• Irrigation farming is practiced in those Huma Java & Indonesia areas where rainfall is seasonal and the amount is not satisfactory for crop Jhum N.E. India production. In the river valleys of the Bewar Bundelkhand world this farming is practiced. www.OnlineIAS.com • Deepa Bastar Dry farming: areas having very little rainfall less than 50cm and very little Jara & Erica Southern States irrigation facilities practice dry farming. Crops which can bear the high cost of Batra South-eastern Rajasthan production e.g. cotton and wheat is Podu Andhra Pradesh grown under this method.

Kumari Western Ghats in Kerala The types of farming practised are discussed below: Kaman, Winga

A. Shifting cultivation & Dhavi Orissa

A primitive form of agriculture practiced B. Plantation farming: mainly in the tropics wherein a plot of land in cultivated for a few years, until the production An estate farming mostly in tropical and declines due to soil exhaustion. Slash and burn subtropical regions devoted to large scale pro- method is practiced in which forests are cut and duction of one or more cash crops e.g. Coffee, Rubber and Tea, etc.

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C. Truck farming: els). Approximately two-thirds of the wheat pro- duced in the world is used for human food and Refers to the intensive cultivation of veg- about one-sixth is used for livestock feed. Indus- etables for the market and therefore is corre- trial uses, seed requirements, and post-harvest sponding to the term market gardening that is losses account for the remaining withdrawals usually done in U.K. Truck farms, however, ap- from the world wheat granaries. The geographi- pears to be more specialized and truck farms are cal concentration of wheat is found between 30- generally situated farther from the markets. 55°N latitude in the Northern hemisphere and between 20-40°S in Southern hemisphere. D. Mixed farming:

Conditions of Growth It refers to the combination of agriculture and livestock farming. (a) A minimum temperature of 16°C and bright sunshine for ripening, and 100 frost free days. E. Collective farming: (b) A mild moist season with annual rainfall A type of agricultural organization started in ranging between 50 cm and 100 cm. former USSR and then adopted in Eastern Europe, China, N. Vietnam and N. Korea. Large (c) A relatively stiff, preferably loamy and non- farms covering thousands of hectares are man- acidic soils. aged by co-operative bodies and the govt. and called Kolkhoz and Sovkhoz respectively. The (d) Level or slightly rolling lands to facilitate mechanical methods of farming. workers receive shares of the sale proceeds as wages, according to the work done. In terms of net output four countries viz. Kibbutz- community farming in Israel. These Russia, U.S.A., China and India contribute over are smaller than the collective farms. 50% of world production. But temperate coun- tries like France, Spain, Argentina, and Austra- lia F. Nomadic Herding: are also important contributing most (20%) of It's a type of shifting pastoral farming in world's wheat. which pastoralists move from one place to an- Distribution of Wheat: other in search of good pasture. It is mainly prac- ticed in arid and hilly regions and primitive so- USA: According to regional diversity of cli- cieties. Animals like Cattle, sheep and goat are mate four major wheat growing belt can be dis- reared for milk, meat, wool etc. tinguished they are:

G. Transhumance: (a) White wheat region of the Colombian plateau; It is also concerned with animal husbandry but in thin the people have their permanent (b) Hard red spring wheat of the N provinces; settlement and they move to a suitable place only in adverse climatic condition and return back to (c) Hard red winter wheat of the W and S www.OnlineIAS.comprovinces, and their homeland as the climatic condition be- comes normal. Mountains of Himalayas, Rockies, (d) Soft red winter wheat of the Southern Alps and Norway are famous region for tran- states. shumance. In India Gaddis of Himachal Pradesh and Bakarwals of J&K practice transhumance. Russia: The wheat production is concen-

trated in black chernozem soil belt. They are Food Grains (a) The north Caucasus region producing I. Wheat winter wheat in the south-western part and

Wheat is the dominant grain of world com- (b) The Volga region of the spring wheat merce and is the staple food of millions of people. It is also an important part of the daily diet of (c) The eastern regions including trans-Ural many millions more. The world wheat market is and western Siberia producing best hard enormous. Annual global wheat consumption spring wheat in the world. is in excess of 550 million tonnes (20 billion bush-

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China: China is the largest producer of the world. Sichuan basin is the largest producer wheat in the world. Wheat is produced in the followed by Red Basin, riverine flood plain of area irrigated by the Huang-Ho, Hopei, Shansi, Yangtze basin, Yunnan and Kweichow prov- Shantung and Hainan districts are important inces, Fukien, Kwanghing and Kwangsi and wheat producing areas. Hunan, Kiangsi and Chungking province. The soil fertility, use of manures and unified management Australia: The important wheat growing are responsible for higher productivity. areas are in the fertile plains of Murray Darling basin and in the S.W. Australia. Uncertainty of India is the second longest producer of rice in the world. rainfall, great distance from markets and low population are main deterrents. Bangladesh is the third largest producer of

Argentina: Wheat farming is confined to the rice, though rice is grown everywhere Dacca, great wheat crescent which is bounded to the maymansingh, Bakharganj, Faridpur, Barisal districts account bulk of the country's output. west by the 40 cm isohyets and to the east by the 100 cm isohyets lines. Japan: rice is grown throughout the coun-

try; per hectare production is very high. But high Export:- domestic demand and limited land forces the USA, Canada, Argentina and Australia are country to import rice. leading exporting countries whose share is al- The fertile alluvial plains of Irrawady in most 80%. Britain, Japan, Germany, Belgium, Myanmar, the Red Basin of North Vietnam, the Holland, Italy are leading importers. Mekong Basin of South Vietnam, and the Menam II. Rice Basin of Thailand are also notable in rice pro- duction. Rice is also grown in Nile valley and Rice is normally grown as an annual plant, delta of Egypt, S.E. Brazil and Gulf of Mexico in although in tropical areas it can survive as a the USA and Po river valley in Italy. perennial crop for up to 30 years. The rice plant Export:- can grow to 1-1.8 m tall, occasionally more de- pending on the variety and soil fertility. Very meager amount of rice (2 to 5%) come to

Conditions of growth the international market. The major rice ex- porting countries are China, Myanmar, USA, (i) Hot and humid climate - high degree of Thailand, Brazil, India and Italy. Major import- temperature ranging between 20°-27°C and ing countries are Indonesia Korea, Hongkong, minimum rainfall 120 cm. It also requires Srilanka and Bangladesh. water logging particularly in the early parts III. Maize of its growth and deep clayey loams.

Maize is widely cultivated throughout the (ii) Rice needs a level surface to ensure annual world, and a greater weight of maize is produced flooding of the fields. It's most ideal habitat each year than any other grain. The United States is therefore, the greatwww.OnlineIAS.com riverine flood-plains produces (42.5%) of the world's harvest; other top of the world. producing countries includes China, Brazil, Mexico, Argentina, India and France. Distribution: Conditions of growth: Monsoonal low lands of South-east Asia is the most outstanding region for rice growing in the No other cereal is cultivated under such di- world-accounting for 85% of the total rice acre- verse climatic conditions and no other cereal crop age of the world and produce 90% of the world is so widely distributed both in tropical and output. The noted rice producing countries in the warm temperate latitudes. Even then favorable world include China, India, Indonesia, Bangladesh, conditions are: Thailand, Vietnam, Myanmar, Italy, Spain, USA (i) Temperature 20-25°C and Brazil are other producing countries. (ii) Long and warm summer with considerable China

China is also the largest producer of rice in

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rainfall followed by little rainfall of autumn not used for rice/wheat short supply of and cold winters is ideal and optimum moisture led barley to be grown in further conditions forward to the pole in the north and high on the high monitions slope. (iii) Rainfall 7-15 cm per month and during season of 130 to 170 days. Distribution:

(iv) Deep rich soils of the sub-tropical latitudes Russia is the largest producer of barley in the with high nitrogen content well drained world. No other can causes is the most im- plain lands are most commonly preferred portant producing zone. China is the second for maize growing. largest producer of barley.

Distribution: In Europe the Mediterranean belt is of great importance for barley cultivation. From Medi- USA, Brazil, Mexico, China and Russia account terranean region in the south-European barley for 65% of the total world maize production. belt structures as far north's Arctic Circle and from the Atlantic coast to the trade. USA accounts for half of the world's maize production. The Corn Belt extends from central Export: USA & Canada export 60% of the Ohio to Central Nebraska. Iowa, Illinois, Indi- world barley Argentina, Denmark and France are ana, Minnesota, Pennsylvania and Nebraska are other exporters. Germany, UK, Japan and Neth- the principal maize producing states of the USA. erlands import almost half of the world's barley. In this belt maize is grown as rotation crop. V. Oats In Argentina, Corn belt lies in the humid Pam- Oats are the hardest of all cereals. It is al- pas region, wet of the Parana river. Despite con- most confined to northern hemisphere. The tributing only 3.5% in world production Argen- oats are of paramount importance in the old tina exports more than half of the total export. damp countries like Greenland, UK, Sweden, China is the second largest producer. Norway and grown in a significant propor- tion by the countries of Central and Eastern Brazil - Minas Gerais, Sao Paolo, Rio Grande Europe. Russia is the largest producer of oats are important maize producing zone. The pro- followed by the USA, Canada, Germany, duction is almost double of Argentina but con- France and Poland. sumed locally. VI. Rye Export: 16 per cent of the total global output enters world market is sale. Argentina, USA, Rye is essentially a European agro-product France and South Africa are major exporting coun- and is grown primarily in Eastern, Central and tries. Japan is the largest buyer, followed by Neth- Northern Europe. The main rye belt stretches from northern Germany through Poland, erlands, Italy, Spain, UK, Germany and Denmark. Ukraine, Belarus, Lithuania and Latvia into cen- IV. Barley www.OnlineIAS.comtral and northern Russia. Rye is also grown in North America (Canada and the USA), in South Barley is a widely adaptable crop. It is cur- America (Argentina, Brazil), in Turkey, in rently popular in temperate areas where it is Kazakhstan and in northern China. grown as a summer crop and tropical areas where it is sown as a winter crop. Its germina- VII.Sorghum tion time is anywhere from 1 to 3 days. Barley USA is the largest producer of Sorghum, in likes to grow under cool conditions but is not China Sorghum is called Kaolin. In China, sor- particularly winter hardy. Barley is more toler- ghum is fermented and distilled to produce ant of soil salinity than wheat maotai, which is regarded as one of the country's Conditions of Growth most famous liquors. VIII. Millet (i) A moderate amount of rainfall 75-100 cm. (ii) Short growing season, resistant to a number Millets are major food sources in arid and of conditions, grown on lands which are

www.OnlineIAS.com N. Kalyana Chakravarthy 91 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] semi-arid regions of the world and India is the Export: largest producer of millets in the world. The leading cotton producing nations like IX. Cotton the USA, Egypt, Mexico, Brazil, Peru, Sudan, Pa- kistan and Turkey are all leading exporters of The largest producers of cotton, currently cotton in the world. The countries alone account (2009), are China and India, with annual produc- for 50% of the world's export. Japan is the single tion of about 34 million bales and 24 million bales, largest buyer of cotton in the world. respectively; most of this production is consumed by their respective textile industries. The largest X. Jute exporters of raw cotton are the United States, Jute is a rain-fed crop with little need for fertil- Conditions of growth izer or pesticides. The production is concentrated in Bangladesh and some in India. The jute fibre (i) Uniformly high temperature 20-25°C comes from the stem and ribbon (outer skin) of the during the growing period. jute plant. The fibres are first extracted by retting.

(ii) A frost-free season of 100-200 consecutive Conditions of growth days. (i) A hot and humid climate with a minimum (iii) Annual rainfall ranging between 60-90 cm. temperature of 28°C and more than 200 during the maturing period higher rainfall cm of rainfall with 80 to 90% humidity is detrimental. especially during the season.

(iv) Well drained fertile soils with high water (ii) Cheap and plentiful supply of labour is retentive capacity. another contributing factor.

(v) Plentiful supply of cheap labour. India, Bangladesh and China account for

almost 98% of the world's jute production. Distribution: Distribution: The crop is quite widely distributed in the sub-tropical latitudes and a host of countries are Bangladesh - Jute is the most important engaged in its production, but a few countries cash crop in Bangladesh and is grown in almost viz. Russia, USA, China, India, and Egypt domi- all the districts. The jute belt of Maymansingh, nate the output. Decca and Tippera and the old valley of

USA: The area to the S.W. of Mississippi Brahmaputra is noted for very higher grade of river enjoys the overwhelming superiority in jute. On the banks of river Jamuna, Pabna, Bogra cotton cultivation. Texas, Oklahoma and Arkan- and Rangpur district are also famous. sas are the most important. Mississippi, Nevada, Maymansingh is the largest producer of jute in the world. California are also important cotton producing states. USA is the second largest producer of China is the largest producer of jute in the cotton in the world. www.OnlineIAS.comworld. Jute producing regions are principally

China: Great plains of Northern China that located to the south of Yangtze Kiang river the encompasses the Hwang Ho, Yangtze Kiang, important provinces are Guangdong, Zhejiang, Guanik, Jiangsu and Hunan. Weitto valley and Szechwan Province, china is the largest producer of cotton in the world. India is one of the largest producers of the

jute in the world. Egypt is the producer of best quality cotton in the world. The reasons for importance of raw Apart from these countries, Russia, Brazil, cotton in the world are (i) highly suitable climatic Myanmar, Thailand and Nepal are also grow- and edaphic condition (ii) high demand for Egyp- ing jute. tian long-staple cotton; (iii) long experience in cotton mixing. Egypt accounts for 60-70% pro- Export: duction of long staple cotton in the world. Bangladesh is the largest exporter in the

www.OnlineIAS.com N. Kalyana Chakravarthy 92 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] world, contributing 65% of the world's export. (iii) Large supply of labour India (5%), Nepal and Thailand are other ex- porters. U.K., Germany, Japan, Pakistan and Kursk, Ukraine and Monrovia are important Spain are important importers. producing areas. Italy produces the best quality hemp, in the Po river valley and volcanic plains XI. Flax in the south. India, Yugoslavia, Rumania, Hun- gary, Poland and Spain are other notable pro- Flax is an erect annual plant growing to 1.2 ducers of hemp in the world. m (3 ft 11 in) tall, with slender stems. In the United States, three states, North Dakota, South XIII. Silk Dakota, and Minnesota, raise nearly 100% of this plant. It is used for manufacture of linen, is pro- Silk is a natural protein fiber, some forms of duced from seed from which linseed oil is ex- which can be woven into textiles. The best- tracted. known type of silk is obtained from cocoons made by the larvae of the mulberry silkworm Bombx Conditions of growth mori reared in captivity. The birth place of silk is China as from there it spread to Japan, India, (i) Grows in areas having moderate rainfall Southern Europe and Western Asia. distributed evenly during the growing periods warm and uniforms summer Commercial production of silk involves four temperature with high humidity are different stages: (a) growing of mulberry trees required for the growth of plant. (b) rearing of silk (c) tendering of cocoons (d) reeling of silk. (ii) Clay loam soil so as to able to retain moisture. The temperature should be between 20-30°C each cocoon has 762 to 915 meters of filament. For (iv) Constant weeding is required in order to the ideal growth of cocoon, high temperature and ensure a better growth of the plant. heavy rainfall is required. The mulberry trees can (v) Like jute it requires rottening be grown on poor acid and infertile soils. This is why they are relegated to the rugged lands or hilly tracts which are not available for food production. Distribution:

Practically all the flax fiber is produced in Distribution:

Europe, Russia, Poland, France, Belgium, Holland Japan is leading producer of silk in the world and Czech Republic are the principal producers. - the production is taking place from northern Russia is the largest producer. More than Honshu to South Kyushu. The great concentra- 80% of the world's flax comes from Russia. Kahn tion of production is in Lake Suwa region of Leningrad and Smolensk are the chief areas of Central Honshu - high temperature heavy rain- production. Poland, France and Belgium's place fall and rugged topography is easily available. come accordingly in production after Russia. China - Production is centered in south and XII. Hemp www.OnlineIAS.comwest of Shanghai, in parts of Szechwan basin, in the delta region of Si-Kiang near Canton. Shantung Hemp is one of the faster growing biomasses Peninsula also participates in production. known, producing up to 25 tonnes of dry mat- ter per hectare per year, and one of the earliest Korea - the relief, soil and climatic condi- domesticated plants known. For a crop, hemp is tions favors the growth and throughout the very environmentally friendly as it requires few country it is the subsidiary occupation of the farmers. pesticides and no herbicides.

Conditions of growth In Europe - PO valley of Italy is famous for silk production. France is also important. (i) Moderate rainfall, well distributed over growing period of 110 days warm India is the only country where all four types conditions and high humidity. of raw silk are produced- Mulberry, Eeri, Tusser, and Muga. (ii) Well prepared and fertilized soil and

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Export: Japan is the largest exporter contrib- areas. In small quantity of tea is also grown in uting more than 70% followed by China, Korea Kandy and in the hills behind Gale and and Italy. USA is the largest country importing Malara. Srilanka is the second largest exporter of more than 60% followed by UK, France, and In- tea in the world. dia. Japan - Tea is grown mostly on the Pacific XIV. Tea coast on the low terraced slopes of the moun- tains enriched with highly fertile volcanic soils. Tea is the agricultural product of the leaves, Uzi and Shizouka districts of southern Honshu leaf buds, and internodes and is the most popu- are most important tea growing areas. lar drink in the world in terms of consumption. Its consumption equals all other manufactured Indonesia: In Java island, the production is drinks in the world - including coffee, chocolate, concentrated the slopes of two extinct volcanoes soft drinks, and alcohol - put together.[4] Most Godak and Salak on the western side. In N.East part of Sumatra tea is also grown. tea consumed outside East Asia is produced on large plantations in India or Sri Lanka. Taiwan is known for its wuling tea. The ter-

Conditions of growth raced fields around Taihoku are important tea growing areas. (i) High temperature of 27°C abundant rainfall of about 200 cm and high amount of Kenya is an important producer outside the moisture in the air. This climatic condition monsoonal realm. There tea is grown on the confines the cultivation in rainy tropical Nairobi high lands Malawi, Mozambique at Tan- zania are other producing countries in Africa. and humid tropical regions. High humidity, heavy dews and morning fog favors rapid Export: development of young leaves. India and Srilanka are first and second larg- (ii) Relatively high sloping ground - so as to est exporter of tea in the world followed by In- prevent water logging in the plant and donesia, Bangladesh, Japan and Kenya. Euro- should contain iron content acidic in nature. pean and American countries are major import- (iii) Large and cheap labour supply. ers e.g. U.K., USA, Russia, Australia, Canada, Netherlands and Pakistan.

Distribution: XV. Coffee

These environmental and economic features Coffee is a brewed drink prepared from are present in South and East Asian countries roasted seeds, commonly called coffee beans, of and hence more than nine-tenth of production the coffee plant. They are seeds of coffee cher- ries comes from there continuously. More than 75% that grow on trees in over 70 countries. Cof- fee is of the global output of tea comes from India, usually propagated by seeds. The traditional China, Srilanka, Japan and Indonesia. Outside method of planting coffee is to put 20 seeds in the realm of monsoonalwww.OnlineIAS.com Asia. The tea is grown each hole at the beginning of the rainy season in USSR Kenya, Malawi and Turkey. Conditions of growth India is the largest producer of tea in the world. (i) Warm climate conditions annual range of temperature is between 21° and 26°c and China: Chief production areas are lying be- winter temperature should not fall below 10°. tween the Yangtze and Sinkiang valleys. Red soils of the hilly areas of the provinces of Hunan, (ii) High rainfall ranging between 125 and 150 Anhui, Sichuan, Zhejiang and Fujian are impor- cm. The hot rainy season helps the plants tant producing states. China has the largest area to grow rapidly and dry winter seasons under tea cultivation in the world. China is the favors the proper ripening and harvesting. largest producing green leaf tea in the world. (iii) Well drained fertile, soil rich in plant nutrient Srilanka - Tea states are highly concen- such as iron and potash are useful. Terra trated in the Nuwara Eliya and the Badulla

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Roxa soil is ideal for coffee plant. The plant developed in the regions having about 27°C of grows usually on hill slopes and highlands temperature and 200 cm of rainfall. It requires having in altitude of 1800 to 2500 ft. deep clay soils rich in iron and potash and cheap labor supply is also significant. Distribution: Distribution: Four major coffee producing regions in the world are: West African countries of Ghana, Ivory Coast, Cameroon and Nigeria are the most im- (a) South American region comprising Brazil, portant Cocoa producers in the world account- Columbia, Ecuador and Venezuela and ing for more than 70% of the world production, Peru - account for 50% of the world's rest of the production come from South Ameri- production. can countries including Brazil, Ecuador, Venezu- (b) Caribbean Region - Mexico and Al ela, Dominican Republic and Mexico. Ghana is Salvador, Guatemala and Costa Rica - 15% the largest producer and exporter of cocoa is the of the world production. world-contributing half the country's export earn-

(c) Africa including Uganda, Ivory Coast, ings. Cocoa cultivation is concentrated in the form Angola, Ethiopia, Malawi, Congo and of a triangle which includes the three important towns of Accra, Kumasi and Takoradi. Kenya - contributes 30% of world output.

(d) S.E. Asia comprising Indonesia Indian and Nigeria - Important Cocoa growing regions Philippines - 5% of the total output. in the country are concentrated around Ibadan in S.W. Nigeria which has the largest acreage.

Brazil - Four states of Sao Paulo region Brazil is the largest South American pro- Parana, Espirito, Santos and Minas Gerais are ducer of cocoa. Bahia distt in N.E. Brazil is the leading producers. Good soil and good drain- most important region. Ecuador - most of the age condition and intensive network of trans- cocoa growing areas are concentrated in the portation apart from the favorable climatic con- Guayaquil Lowlands which provides almost ditions favor the concentration in this region. optimum climatic condition for cocoa growing. Brazil is the largest producer and exporter of coffee in the world. Papua New Guinea is the most important producer of cocoa of Oceania contributing a little Columbia is the second largest producer. over 2% of world production. The great majority coffee estates are located with Export: in the high mountain slopes of the Andes- around Bogotá, Madellin, Manizales and Tolima The West African countries viz. Ghana, are the principal centers of the regions. Ivory coast, Cameroon and Nigeria are more or African Countries - The rainy uplands, rich less solely dependent on the earning from the fertile soils and favorable climatic condition in exports of cocoa, Ghana is the largest exporter addition to abundant supply of cheap labor lead followed by Nigeria, Brazil and Ivory coast, USA to the rapid increase inwww.OnlineIAS.com output in recent years. is the largest importer followed by UK, Germany Ivory Coast is the third largest producer of cof- and Netherlands along with France, Japan, Bel- fee in the world. gium and Italy.

XVII. Sugarcane Export: Sugarcane growing countries of the world More than 80% of total output enters the are lying between the latitude 36.7° north and global trade market. Brazil, Columbia, Ivory 31.0° south of the equator extending from tropi- Coast Uganda and Mexico are the chief export- cal to subtropical zones. ing countries. USA, Germany, France, Italy, the Netherlands and Japan are the main buying Condition of growth countries. USA is the largest importer of coffee. (i) Warm climatic conditions the annual

temperature ranging between 21-27°C XVI. Cocoa

Cocoa is essentially a tropical crop, is best

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(ii) It grows best in the regions having about producing state.

125 cm of annual rainfall. If the amount of Mauritius and Fiji is two important islands, rainfall exceeds the optimum level, the countries grow sugarcane mainly for experts and sucrose content declines. their economy is based on cane cultivation. (iii) Deep, well drained fertile soils are most XVIII. Sugar Beet important for sugarcane cultivation water logging is highly detrimental. Sugar beet is a plant whose root contains a (iv) Sugarcane growing is, highly labor intensive high concentration of sucrose. It is grown com- in nature. Therefore, densely populated topi- mercially for sugar production. Sebewaing, cal countries are most imported for sugar- Michigan is known (to Americans) as the sugar cane cultivation. beet capital of the world.

Distribution: Conditions of growth

Sugarcane is most widely grown in a num- (i) Sugar beet is a native of temperature climatic ber of tropical and sub-tropical countries but the regions with moist and mild winter and two principal sugarcane areas are (i) South-east moderate summer temperature. It is very Asia-India, Pakistan, China, Indonesia and Thai- sensitive to annual ranges of rainfall which land and (ii) Latin America - Cuba and Brazil. should necessarily be around 60-65 cm.

China - contributes about 6% of the world's (ii) Loose friable deep soils which favor sugarcane rugged Terrain limit the cultivable uninterrupted penetration of the beet roots. areas only to river basins. (iii) Since it is a highly capital intensive crop, Indonesia - cane is most intensively a culti- its cultivation limited only to the rich vated in the Java islands where the climo- edaphic- economic condition is ideal. countries.

India is the largest producer of cane in the Distribution: world. Europe and America have over whelming Pakistan - produces a little over 4% of the superiority in beet cultivation since they contrib- world output - cultivation is mainly concerned ute almost 85% of the global output. in irrigated plains. Russia is the largest producer contributing the Brazil - produces more than 15% of the fourth of the global output. Apart from Russia world output and comes next only to India - due France, Germany, Czech Republic is the dominant to suitability of environmental conditions. The producers.USA is the third largest producer con- principal area of concentration include (a) the tributing more than 8% of global output-mainly coastal lands of the north-east in the states of concentrated east of the Mississippi river and in Prarahiba, Peruamnbuo, Alagoas and Bahia (b) the plains stretching from Montana to South Colo- The Minas Gerais district and (c) the coastal rado in the Snake River Valleys. The bulk of plains North-east of Rio-www.OnlineIAS.comde-Janerio. country's output comes from California. China, Cuba - its economy is to a great extent de- Japan and Turkey are other producing countries. pendent on sugarcane cultivation - is the third XIX. Tobacco largest producer of sugarcane in the world. The favorable environmental and economic conditions Tobacco is an agricultural product processed led the concentration in the districts of Havana, from the leaves of plants in the genus Nicotiana. Metanzas, Orienta and Santa Clara. Nearness to It can be consumed, used as an organic pesti- vast American market is an added advantage. cide and, in the form of nicotine tartarate.

Australia - Produces little over 4% of the Conditions of growth world's sugarcane cultivation predominates along the east coastal plains of Australia stretch- (i) The plant prefers considerable warmth and ing from northern New South Wales to North moisture; temperature, rainfall and soil affect Queensland. Queensland is the most important the quality. Excessively heavy rainfall reduces

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yield and increases the acid content in the leaf. provide the most ideal ground for rubber growing. Gently undulating surface conditions Distribution: prevent water logging and check soil erosion.

Distribution: Most of the producing areas are in the south- ern part of the middle latitudes and along the north- South-east Asian countries including Ma- ern margin of the topics - USA, China, Brazil, India layan Archipelago, Indonesia, Thailand, Srilanka and Russia are the chief producing countries. and India have maintained their monopolistic con-

China is the largest producer - production trol over global production of natural rubber. Leba- non and Nigeria are other producing countries. takes place in the irrigated region of the Chengdu in the Red Basin and in the Sikiang valley in the Malaysia ranks third in naturals rubber pro- south. duction. Accordingly favorable rainfall and tem- perature, extensive flat coastal plain cheap labor USA is the second largest producer - North and government patronage helped a lot to expand Carolina, South Virginia, Georgia, Northern rubber plantation. Here rubber is grown over 30% Florida and South Carolina participate in to- of the cultivate land. Malaysia is the third pro- bacco production. North Carolina account 95% ducer and exporter of rubber in the world. of the national output. Indonesia - Ranks second only to Thailand Indonesia - Tobacco is produced in eastern in production. Mostly in Sumatra islands, and java and North Eastern part of Sumatra islands. climatic condition prevail here but small hold- The quality of cigar is very high. ings, over taxation, lack of re-plantation and Philippines - Cagayan valley and glaciers over-exploitation of trees are reason for lower production in Indonesia. coastal plains of Luzon, and the central Visayan Islands, Panay and Cebu. India - Kerala accounts for 90% of the na-

tional rubber output. Brazil: Tobacco is grown on the eastern coast plain. Thailand is the largest producer of rubber in the world. Southern Thailand out-ranks all Export: other regions.

USA, Dominican Republic, Cuba, India, Tur- Liberia, Nigeria, Ghana and Zaire are the key, Brazil and Zimbabwe are important export- most important rubber producing of countries ing countries, UK, Holland, Belgium, Germany in West Africa hold second place after South- and Spain are the most important. UK is the larg- East Asian nations. est importer country. Export:

XX. Rubber Malaysia and Singapore account for nearly 50% The commercial source of natural rubber la- of the global share of exports. Indonesia accounts tex is the Para rubber tree. Rubber latex is ex- for another 25% of exports. Srilanka and Thailand tracted from Rubber treeswww.OnlineIAS.com. The economic life are other important exporting countries. USA is the period of rubber trees in plantations is around largest buyer of global rubber and account for half 32 years - up to 7 years of immature phase and of the total imports. UK, Russia and France are other about 25 years of productive phase. important buyer. Today, natural rubber is facing stiff competition from synthetic rubber. Conditions of Growth XXI. Coconut (i) Rubber is a tropical crop of the humid tropical countries, therefore, thrives best in The plant grow well in areas of high tem- the regions having high temperature and perature, (25°C) heavy rainfall (over 200 cm) annual precipitation, where temperature is and high humidity, along sea coasts the coco- less than 21°C it may not be grown. Rubber nut trees grow well. survives best in the regions with about 150 Distribution: to 250 cm. of rainfall. Coconut production is concentrated within (ii) Deep loose and well-drained alluvial soils

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20° on either side of the equator. The Philippines, Canada is the largest exporting country fol- Indonesia, New Guinea, Fiji, Solomon Island, lowed by USA, India and Argentina, UK, Malaysia, Srilanka, Mozambique and India are Holland, Germany, France and Belgium are important producing countries. importing countries.

Philippines produce almost 30% of the total • Sunflower: global output. Srilanka and Indonesia are sec- Russia and China is the chief producer and ond and third largest producer and exporter of exporters - Germany and UK are chief im- coconut in the world USA, Germany, Holland porters. and UK are chief buying nations. • Sesame: XXII. Oilseeds India and China are main producers. China • Groundnut: is the largest exporting country. India is the largest producer followed by • Soybeans: China, Nigeria and most Africa. India is also the larger exporter of groundnut. USA is the largest producer of Soybeans in the world followed by China, Japan and In- • Linseed: donesia are other producing countries. USA USA is the largest producer of linseed in the accounts for three-fourth of the total Soy- world. Argentina, Canada and Russia are beans exports. Japan is the largest buyer fol- other important linseed producing countries. lowed by Germany and Canada.

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FISHERIES

The principal fishing grounds of the world are located on the plankton rich banks of the Types of Fish continental shelves especially in the cool water Salt Water Fish: They spend their entire life in the of the northern hemisphere in comparatively oceans and seas. high latitudes. In terms of production, Japan is para-mount followed by the CIS, China, Norway Fresh Water Fish: They are found in inland and USA. streams, rivers and lakes.

Anadromous Fish: They are spawned in the Locational Considerations inland rivers but spend most of their life in the (I) Supply of Plankton: Important conditions seas and only return to the rivers to spawn for its presence are (a) Shallow water above and die, e.g. Salmon.

continental shelf (b) Cool Water- Plentiful Pelagic Fish: They live at or near the surface in polar water where cold & warm currents of water like herring. meet. (c) Land- derived minerals which nourishes planktons. Demersal Fish: They live at the bottom like

cod, haddock. (II) Cool Climate: Best developed where temp. is below 20°C; tropical water is too warm 1. Pelagic: Light loving & found near the so fishes are of less commercial value while in ocean surface and form schools e.g. the temperate latitude water is cool so most suitable; fish cannot be kept long in hot, Herring: most important catch of N. moist tropical conditions. While the Atlantic region & also the chief fish caught in Japan & China. temperate land of cold winters originally provides natural ice for preservation of fish. Mackerel: generally found south of the main (III)Physical & Environmental Influences : Both herring areas, e.g. in the Mediterranean Sea, Atlantic and Pacific ocean coast-lines of Off- South Scandinavia, Off- Cornwall (UK), Off- Carolina (USA), Yellow sea. middle and high latitude in N-Hemisphere are very much indented and are backed by strong Sardines:temperate water fish; relief. There are sheltered inlets & estuarine Mediterranean sea, Bay of Biscay, Coastal coasts that make ideal sites for fishing ports New England States are its main regions. & villages. The ruggedwww.OnlineIAS.com mountains & short Brisling: temperate water fish; off-south growing period in Norway, Hokkaido, Norway. Iceland, Alaska restricts agricultural activities & people take to the sea to enrich their diet. Anchovies: temperate water fish, Off- In S-Hemisphere fishing activities are Europe, Peru (90% of Peru catch).

hampered by lack of harbours or of labour. Menhaden: off-USA (from Newfoundland In Argentina & Australia meat & other to Caribbean Sea); due to oily nature foodstuffs are so plentiful that it has not been unsuitable for human, generally used as necessary to develop a fishing industry. animal feeding, fertilizer, soap, etc. (IV)Moderate or Large Population: It is a labour Capelin: Like: Menhaden, caught in the intensive industry, small scale fishing in well- N.E-Atlantic. populated areas as China, Japan, etc. 2. Demersal: not light loving, on ocean bottom, also known as ‘White Fish’ e.g.

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Cod: in terms of value more important than land and to a little extent in its Herring; North Sea, Off- Norway & surroundings. Iceland, Grand Bank off Newfoundland. Leading Fishing Areas Haddock: N. Atlantic Coast. (1) North West Pacific Region: Halibut: Off- British Columbia, N.W-USA, • Extends form Bering Sea in the north to Hake and Flat fishes like Plaice, Sole, Philippine sea in the south bordering Flounder. Central & Northern Japan, N. China, Korea & NE. Russia. Tuna: Japan, Mediterranean Sea, Indian Ocean, California. • Mixing of Kuroshio Warm & Oyashio Cold currents favours the vigorous II Fresh Water Fish (10%): They rarely swim growth of fishes and form the greatest in large shoals & their fishing areas are fishing ground of the world. rather restricted. Inland fishing is important in former USSR & E. Asia. • Japan leads the world in fish production (9.2%in 1993). Other important countries Trout, Perch, Pike, Salmon: N.America & are Baltic nations, Russia, China, Korea. Europe. (2) North-East Atlantic Region: Sturgeon: Caspian Sea, Black sea, Volga, Danube, Dnieper, St. Lawrence. • Comprising shallow waters of the European coast extending from the Barents Carp: China & Japan. Sea in the north to the Bay of Biscay.

Eels: Denmark, Netherlands, USA. • ‘Dogger Bank’ of the North Sea is the most important fishing ground of this III Anadromous Fish: Both fresh water& salt region. water fish. • The warm waters of North Atlantic Drift Salmon: N. America (from Alaska to keep the coast open, throughout the year. Oregon on Pacific coast)-Young salmons live in sea but after 2-5 yrs they return to • Major fishing countries are Norway, the stream where they were born to lay Sweden, Denmark, Netherlands, France, Iceland, UK. their eggs & die. Today Salmon’s greatest haul is in Alaska. • ‘Grimsby’ is the greatest fishing port in

the world, in variety & value of fish Major Fishing Regions landed.

• North - West Pacific Region: It extends • Cod, Herring, Halibut, Sardines form the from Pacific Bering Sea in north to main catch of this region. Philippines Sea in the South. In this Region Japan is the leadingwww.OnlineIAS.com producer of fish. (3) North West Atlantic Region:

• North-East Pacific Region : It extends from • Meeting of warm Gulf Stream & Cold Alaska to California along the western coast Labrador favours the growth of plankton. of North America Salmon, Pilchard, Tuna, Sardines and Halibut are the important • Cod, Perch, Herring, Haddock, Lobsters, catch of this region. Oysters are the main catch of this

region. • North Atlantic Region: It extends from the Arctic circle in the north to the borders of • Maximum fishes are caught from the the Mediterranean Sea along the West coast of Newfoundland & Novascotia. European Coasts. • Chesapeake Bay is famous for oyster • North-West Atlantic Region: It extends catches. mainly between long island and Newfound

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• Halifax, St. John, Boston, New York are • It is noted for Salmon, Pilchard, Tuna important fishing ports of this region. & Halibut.

(4) North-East Pacific Region: The deep waters in the continental shelf off- Alaska & the British Columbia are the best • From Alaska to California along the Halibut fishing source of the world. western coast of N. America.

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MINERALS

Minerals generally occur in any of the following Reserves:1. Former USSR formations: 2. India 1. Minerals found in sedimentary beds or horizontal strata are mainly coal and some 3. USA grades of Iron ores. Other minerals of this origin are gypsum, potash and salt. 4. Brazil Petroleum also belongs to this category. Production:1. Former USSR

2. Alluvial Deposits contain those minerals 2. Brazil which are resistant to erosion e.g. gold, platinum and tin. 3. China

3. Some metallic minerals like tin, silver, copper, 4. Australia zinc and lead are obtained from cracks, 5. India. crevices, faults or joints in rocks. The smaller varieties of such occurrences are called Distribution veins and the larger lodes. • India: 4. Deep weathering products also contain some of the mineral resources and bauxite, the (1)Orissa- Mayurbhanj, Keonjhar, ore of aluminium is formed by this process. Sundergarh

(2) Bihar- Singhbhum Classification of Minerals

(3) M.P.-Bailadila Industrial Metallic Mineral: Iron.

Non-Metallic Minerals: Salt, Sulphur, (4) Karnataka- Chikmanglur, Chitra-durg, Potash, Nitrates and precious stones like · Tumkur, Bellary

Diamond. • Former USSR: 40% of world reserves; Non Ferrous Metallic Minerals: 50% is obtained from European part.

Aluminum, Copper, tin. (1) Krivoyrog Region (Ukraine)

Ferro-alloy Metallic Minerals: Manganese, www.OnlineIAS.com(2)KMA (Kursk-Magnetic-Anomaly) in Ukraine. Vanadium, Cobalt, Molybdenum, Nickel. (3) Kerch Peninsula Power Minerals: Coal, Petroleum and Gas. (4) W-Azerbaijan. Precious metallic minerals: Gold, Silver and Platinum. (5) Ural Region- Sverdlovsk (N. Ural), Nizhny Taghil (C-Ural), Magnitogorsk (S-Ural). Iron Ore (6) Kuzbas Region-Kustanay (Kaza-khstan). Important Ores: (7) E-Siberia-Krasnoyarsk, Angara. a) Magnetite (Iron content > 70%), (8) Karaganda. b) Hematite (Iron content = 55-70%), (9) Kutnai (Kazakhstan) c) Limonite (iron content = 40-55%), • USA: d) Siderite (iron content = 10-45%). (1) Lake Superior Region: Mesabi (Limonite,

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70% of US Production), Vermilion, • Britain: (1) Scunthorpe (2) Frodingham Cuyana, Gogebic, Menominee, (3) Cleveland (4) Midland (5) Scotland Marquette • Spain: (1) Bilbao (2) Santander (3) (2) NE. Region (magnetite) - Adiron-dacks Oviedo region of New York, Cornwell region of • Pennsylvania. Germany: (1) Salzgitter (2) Siegen (3) Siegerland (3) SE Region (Hematite and Limonite) - • Brazil: (1) Carajar in Para district (2) Birmingham, Alabama, Red-mountain. Itabira (SE-Brazil). (4) W. Region - Utah, Nevada, Wyo-ming, • California. Venezuela: (1) Lower Orinoco Valley, (2) Guiana Highland - Cerro Bolivar, El- • Canada: Pau.

(1) Lake Superior region- Steep Rock. • Chile: (1) La Sarena (2) Algarroba

(2) Labrador & E-Quebec- Schefferville, • Peru: Nazca- Marcona area. Wabush city. • Africa: Liberia (Bomi Hills, Mt. Mimba), • China: S.Africa, Algeria, Morocco, Tunisia, (Iron & Steel industry is not developed (1) Shenyang (Mukden) region of Manchuria so ores are exported).

(2) Yangtze Valley- Moon Shan, Tayeh, Copper Wuhan Found almost in igneous & metamorphic (3) Shandong Peninsula rocks in the form of Native, Oxide or Sulphide. Often occurs together with gold, silver, lead, (4) Hainan Island zinc, etc.

(5) Hunan Ores: Cuprite, Malachite, Chalcocite, Coveite, Pyrite. (6) Baotao Production: 1. Former USSR • Australia:

2. USA (1) Pilbara Region of W.Australia: Mt. Goldsworthy, Mt. Whaleback, Mt. 3. Chile Bruce, Mt. Tom Price, Yampi Sound, Mt. 4. Canada Newmann, Tailoring Peak, Koola-nooka,

5. Zambia (2) S. Australian region: Iron Knob, Karlgoorlie, Coolgardie.www.OnlineIAS.com 6. Zaire

• France: Distribution:

(1) Lorraine (2nd important area in Europe • India: after KMA) (1) Bihar- Singhbhum, Hazaribagh (2) Normandy (2) Rajasthan- Khetri, Aguncha- Rampura. (3) Pyrenees • USA: (4) Central Massif. (1) Arizona-Morenci, Globe, Bisbee, Casa- • Sweden: (1) Kiruna (2) Gallivare (3) Grande,

Dannemore (4) Grangeberg (5) (2) Utah- Bingham Kopparberg (3) Montana- Butte

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(4) Nevada Corundum, Kaolin,

(5) New- Mexico Commercial Bauxite has 50% alumina & 7% silica, so it is the most wan-ted ore, (6) Michigan Lake mostly mined in tropical region but • Former USSR: aluminium is manufactured in developed countries where cheaper electricity is (1) Ural Region available. World’s first Bauxite mine was in the village ‘Les-Baux’ in France from (2) Kazakhstan which the ore name bauxite is derived.

(3) S- Georgia Process: Hall-Herault Process, Bayer (4) Armenia Process.

(5) Balkash Lake Production: 1.Australia

(6) Norilsk 2. Guinea

• Chile: 3. Jamaica

(1) Chuquicamata (world’s largest copper 4. Brazil mining town) Distribution: (2) El-Temente • India: Bihar, MP, Maharashtra, T.N., (3) Poterillos Karnataka.

(4) Bradue • Australia: Weipa (east of Gulf of Carpentaria), N.E Arnhem (west of Gulf • Canada: of Carpentaria), Cape York Peninsula.

(1) Sudbury (Ontario) • USA: Arkansas, Georgia, Alabama

(2) Noreda (Quebec) • Former USSR: Urals (Karsnya- Shapochka, Kamansk Ural-Skiy), (3) Flin- flon Turgay.

(4) Sheridan • France: Brignoles (N.E of Toulon), Les Baux (5) Lynn Lake (Manitoba) • (6) Coppermine. Guinea, Jamaica, Brazil, Surinam, China, Malaysia, Indonesia, Turkey

• Zambia: (1) Nechanga (2) Kitwe (3) Exporters: Jamaica, Guinea, Hungary, Mufulira www.OnlineIAS.com Surinam, Greece.

• Zaire: Lubumbashi-Katanga. Tin

• Peru: (1) Morococha (2) Casapatla Ores: Cassiterite or Tinstone (75% Tin) • Australia: (1) Mt. Isa (2) Mt. Morgan generally found in alluvial deposits (3) Mt. Lyell. comprising 80% of world supplies, also occurs in lodes & veins in Bolivia. • Papua New Guinea: Bougainville 2. Indonesia Island.

3. Thailand Aluminium

Distribution: Most abundant metal; 8% of the Earth’s crust. • Malaysia: Kinta valley, Larut Plain, Ores: Bauxite (in the form of oxide), Cryotite (found only in Greenland),

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Keylong Valley, Jelepu Valley. It occurs in quartz veins and as placer deposit. • Thailand: Kra Peninsula, Phuket Production: • China: Yunnan (Geiju), Tauchin, Nanling Shan S. Africa: Witwatersrand, Transvaal, Johannesburg, Lydenburg, Orange Free State. • Indonesia: Bangka, Billiton, Singkep, Mt. of Malacca. USSR: Lena river placer deposit, Ural & Trans-Baikal region. • Bolivia: Potosi, Oruro Canada: Flin Flon, Red Lake region • Nigeria: Bauchi Plateau (Bauchi, Jos, (Hollinger mine is one of the largest mine of the Jaria) world).

• Zaire: Manano, Maniemo Australia: Kalgoorlie, Coolgardie.

• Australia: Cornwall, New England. USA: Salt Lake Region, Alaska

• Myanmar: Shan Plateau, Kayinni Japan, India. plateau Silver

Lead Ores: Argentite, Galena; in lodes or veins. Ore: Galena (Lead sulphide) Lead, Zinc & Production: 1.Mexico Silver are almost found together.

2. Peru Use: Storage batteries, Minium (steel coating red point), Type-metals, Bullet- 3. Former USSR making. 4. Canada. Distribution: Distribution: Australia: Broken Hill, Mt. Isa, Roseberry. Mexico: Chihuahua, Fresnillo, Taxco, Canada: British Colombia, Laurentian shield. Hacienda.

USA: Rockies, Ozark Plateau of Missouri, USA: Utah, Montana, Arizona, Colorado, Butte. Idaho, Utah, Arizona, Colorado, Washington. Canada: Kootenay, Ontario, British Colombia, Quebec. Peru: Cerro de Pasco

Peru: Cerro-de-Pasco. Zinc Bolivia: Potosi. Ores: Zinc-blendwww.OnlineIAS.come (zinc sul-phide), Calamine Australia: Mt. Isa, Kalgoorlie, Broken hills.

Use: In galvanization. USSR

Distribution: Platinum

Canada: Sullivan Valley, Canadian Shield, Always found with other rare metals like N.W-Territories, British Colombia. Osmium, Palladium, Iridium, Rhodium.

Australia: Broken Hill, Mt. Isa. Distribution: Canada:

USA: Missouri, Oklahoma, Kansas. Sudbury Colombia: San

Peru, Mexico, Japan, N. Korea Juan region S. Africa:

Gold Rustenburg

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USA: California Distribution: Former USSR (31%): Nikopol (Ukraine), Chaitura (Georgia), S. Africa Former USSR: Nizhni Taghil, Ural area, (Kimberley, Postmasburg) Brazil (Mines-Gerais), Siberia. Gabon (Maonda), India

Diamond Mica

It occurs as crystals in igneous rock called Ores: Muscovite (white), Phlogopite ‘Kimberlite’. (brown); generally found in the form of placer

deposit ‘Carbonado’ is black diamond used in industry, produced in Bahia, Brazil, Africa (‘Bort’ Production: 1. India (80%) variety). 2. Former USSR Distribution 3. S. Africa. S. Africa (leading gems stone producer), Zaire (mainly Bort) USSR, Ghana, Namibia, Distribution: India (Hazaribagh, Nellore), Angola, Botswana, S. Africa, Venezuela, India USA, USSR, France, Argentina, South Korea. (Panna).

Manganese

Ores: Pyrolusite, Psilomelane, as nodule on sea-floor.

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INDUSTRIES

Industry refers to an economic activity that 3. On the basis of ownership industries can is concerned with production of goods, extrac- be divided into:- tion of minerals or the provision of services. There are several industries like iron and steel indus- try (a)Private Sector Industries: owned and (production of goods), coal mining industry operated by individuals or a group of (extraction of coal) and tourism industry (ser- individuals e.g. Tata Motors, Reliance Industries, Bajaj Group etc. vice provider). Industries can be classified on the basis of raw materials, size and ownership. (b)Public Sector Industries: owned and

operated by the government. Exp - Types of Industries Hindustan Aeronautics Limited and Steel

Authority of India Limited. 1. On the basis of Raw Materials they use, industries can be divided into:- (c) Joint Sector Industries: owned and op-

(a)Agro based Industries: use plant and erated by the state and individuals or a animal based products as their raw ma- group of individuals. Exp - Maruti Udyog Limited. terials. Example - Food processing, veg- etable oil, cotton textile, dairy products (d)Cooperative Sector Industries: owned and leather industries. and operated by the producers or sup-

(b)Mineral based industries: use mineral pliers of raw materials, workers or both. ores as their raw materials. Example - Exp - Anand Milk Union Limited and Sudha Dairy. heavy machinery, building materials and railway coaches. 4. Other Classification:

(c) Marine based industries: use products (a)Raw Material based industries: Iron from the sea and oceans as raw materi- als. and Steel, Sugar, Cement, Fish, Meat, Example - industries processing sea food Milk and Food processing, Rayon etc. or manufacturing fish oil. (b)Power based industries: Aluminium. (d)Forest based industries: Utilize forest produce as raw materials. For example: (c) Skilled labour based industries: pulp and paper, pharmaceuticals, fur- Jewellery, Diamond cutting, Watch, Toys niture and buildings.www.OnlineIAS.com and electronics in Japan, Jagadhari.

2. Size of an industry refers to the amount (d)Transportation based: Trans- Siberian of capital invested, number of people em- Railway region industries, Industries of ployed and the volume of production. Great Lake waterways region of U.S.A Based on size, industries can be classified and Canada, industries of coastal areas into:- of Japan, refineries in coastal areas, Jute mills on the bank of river Hugli, indus- (a)Small-scale Industries: Cottage or tries of Perth. Sydney railway region of household industries like basket weav- Australia etc. ing, pottery and other handicrafts, silk weaving and food processing. (e)Capital based industries: Many indus-

(b)Large-scale Industries: automobiles and tries of developing countries of colonial heavy machinery industries. period established by ruler nations during their colonial period e.g. industries of Zaire

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and Guinea were developed by Belgium. USA:

(f) Market based industries: Textile, Refine- It has greater concentration of iron & steel ries, Electronics, Bakery, Ice-Cream, Bis- in north-eastern part. Here three steel district cuits, Hosiery and other consumer goods. have developed:-

(g)Footloose industries: Industries that can (i) Pittsburg district: Pittsburg has developed be established both in the market as well at the junction of Ohio, Allegheny and as in the raw material source region e.g. Mononga-hela rivers. Local coal, iron-ore Paper industry. from Lake Region, local lime and stone are added advantage. Besides, Pittsburg Factors Influencing Industrial Location Youngstown and Johnstown are important centers. The factors affecting the location of indus- tries are: (ii) Lake shore region: steel centers are located at Buffalo, Erie, Cleveland, Detroit and (i) he availability of raw material, Loraine – Lake’s transport facility and Mesabi are chief locational factors. (ii)land, (iii) Atlantic coastal Region: Maryland, (iii) water, Sparrows Point and Pennsylvania are (iv) labour, (v)power, important centres.

(b)In South-Eastern Region, Birmingham is (vi) capital, the largest center.

(vii) transport and (c) In Western Region, Fontana in Califor- (viii) Market. nia and Provo in Utah are important centers.

Industries are situated where some or all of these Japan: factors are easily available. Sometimes, the govern- ment provides incentives like subsidized power, (a) Honshu: Osaka-Kobe, Tokyo- Yakohama lower transport cost and other infrastructure so that (b) Kyushu: Yawata (50%) industries may be located in backward areas. (c) Hokkaido: Muroran. Major Industries Of The World Japan’s iron and steel industry depends on • Iron and Steel Industry imports of iron ore from India, Philippines, Ma- laysia, Canada etc. and cooking coal from Aus- Russia: tralia and China. Now electric hearth process is The major producing centres are:- widely used to save coal.

(a)The southern districtwww.OnlineIAS.coms – existence of China: Krivoi Rog iron ore, Donbas coalfields, Yeleno-vka limestone, Nikopol’s manga- (a) Manchuria region has the largest steel plant nese and Kirch iron-ore are added ad- of China is at Anshan Fushun. Pensinn and vantage. Zaporozhe, Zhdanov, Toganov Mukden are other important steel produc- are important centres. ing centers. The region accounts for two fifth of China’s steel output. (b)Moscow – Tula region- Tula, Vyksa, Kulebadi and Gorki are important coun- (b) Lower Yangtze Valley: Chungking, tries. Wuhan and Hankow are important cen- ters. (c) Ural Kuznetsk Combine: Magn- itogorsk, Nizhnitaghil, Chelyabinsk and (c) Northern China: Large steel plants are lo- Sverdidlo-vsk are prominent centres. cated at Shantung, Beijing, Anyang and Shensi.

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Germany: cheep labour and low cost of land are fac- tors for helping the growth of industry in Essen, Dusseldorf, Dortmouth, Bochum, this zone. Gelsenkirchen, Duesburg and Krefeld are impor- tant centers because of the extensive deposits of Japan: good quality coal within the region. Presence of Natural humid climate, cheap labour, new Ergyberg and Lahn-Sieg iron and excellent im- and upto date machines, cheap hydel power, big port facilities helped immensely for the rapid markets are important factors of growth of cot- growth of Ruhr- Region iron steel industry. ton textile industries in Japan. Majority of the Other important Areas: cotton mills are located in the following regions:

a) France: Lorraine- Metz, Briey, Nancy and (i) Kwanto Region: around Tokyo and Longway along with Sambre- Meuse field Yakohama.

contributes more than 90% of the national (ii) Kinki Region: Osaka is the main center output.

(iii) Nagoya and b) Australia: Newcastle and Port-Kembla along the coast of New South Wales are (iv) Northern Coastal area, other producing important steel centres. centers.

c) Brazil: Volta Redonda is the most impor- China tant center. China is the largest producer of cotton tex- d) Italy: Naples, Genoa, Aosta and Trieste are tile in the world. The prominent centers are important centers. These plants use scrap Shanghai, Manchuria, Tienshan, Beijing iron-ore. Chuang, Nanchang and Hankow. Shanghai is Export: still the largest center of cotton textile in the country. Large market, cheap labour, local raw Japan is the largest exporter followed by material, coastal location and equitable climatic Germany France, Belgium, Netherlands, South condition are the important factors of location Korea, Italy, USA and Taiwan. These countries of cotton textile industries in this region. Most of account for 80% of the International export. the plants are integrated.

• Cotton Textile Industry U.K. Location of this industry is highly diffused- perhaps due to omnipresent market of cotton Once pioneer of modern textile industry, it textile throughout the world. does not find place even among the ten largest producers Manchester, Paisley, and Glasgow are Russia: important centers.

In Russia Ivanovo and Moscow were the most Other Centres important centres. Stalingrad,www.OnlineIAS.com Kirorabad, and Leningrad are other important centers. Ivanovo is India: (Mumbai, Ahmedabad, Madurai, still the largest center of cotton textile in Russia. Coimbatore, Kota, Calcutta etc.) USA: Italy: (Milan- Manchester of Italy) Concentrated mainly is (i) North-eastern Spain: (Barcelona) area in the southern part of New England states, and (ii) South East area encompass- Production and Trade: ing cotton growing states of North Carolina, South Carolina, Tennessee and Georgia. China, India, Russia, USA, Japan and Italy Providence, New Bedford, Fall River, Lowell, produce more than 70% of world total output Holyoke and Manchester are important cen- of cotton textile in the world. India is one of the ters. Local raw materials, favorable climatic largest exporters of cotton textile in the world. condition, cheap hydel power, local market, • Woolen Textile Industry

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The bulk of the wool is produced by a hand- Important Centres: ful of developed countries- Soviet Union, USA, USA: Chicago, Philadelphia, Boston, Los Japan, UK, Germany, China, France and Italy. Angeles. 1) Soviet Union is the largest producer. The leading centers are the Moscow, Tula, and Former USSR: Moscow, Lenin-grad and iron and steel industries regions Leningrad. Ready market for the product traditional base and abundant supply of UK: Birmingham. raw wool are the important advantages. West Germany: Cologne, Essen. 2) USA: In Massachusetts, Rhode Islands, Pennsylvania, New York, Wisconsin and East Germany: Leipzig, Dresden. New Jersey states the woolen textile indus- Italy: Eulogna try has developed. Favorable cool climate, large-scale sheep rearing in northern plains, Japan: Tokyo-Yokohama, Osaka, Kobe, easy and cheap labour and market facility Nagoya. are the chief factors of localization. China: Shanghai, Canton, Harbin, Tientsin. 3) Italy is a leading producer. Most of the • Chemical Industries plants are located at Naples and Po-river valley. Generally these industries are located near • Jute Textile coal- fields, iron-ore fields and agro- industries like Sugar mill etc. First jute mill was established at Dundee Important Centres: U.S.A (N.E Industrial (Scotland) in 1838; but now only India & region), Former U.S.S.R (Moscow Leningrad), Bangladesh are significant producers. Germany (Ruhr basin– Potash and Sulphur de- • Silk Textile posit area), France.

This industry is confined to tropical and sub- • Petrochemicals tropical regions as silkworm needs a tempera- Those industries are generally located either ture greater than16oC. in the source region or near markets.

Important Centres Important Centres: USA (Texas = 40%, Ala- (a) Raw silk: (i) Japan (50%) (ii) China (iii) bama), Former USSR (Volga is the largest cen- Former USSR (iv) India. tre), Japan (Tokyo- Yakohama)

(b) Silk Textile: (i) China (70%) (ii) Japan • Other Industries

Main Problems: High labour cost and com- A. Farm Machinery: USA (Chicago-Mil- waukee belt), Former USSR (Kharkov), petition with synthetics. Canada (Winnipeg) • Synthetic Textiles www.OnlineIAS.com B. Aircraft Industry: USA (Los Angles, San Main synthetic textiles are: Rayon made Diego, Seattle, New York, Wichita), from cellulose, Nylon, Acrylic and Dacron made Former USSR (Moscow, Gorki, from coal and petroleum. Kuybyshev, Tomsk), UK, France.

Centres: USA (Southern States, Pennsylva- C. Shipbuilding: Requires coastal location nia, New England); Japan; France. of iron and steel industry and large harbours. Centres: USA (East coast), • Mechanical & Electrical Industries For-mer USSR (Leningrad, Vladivostok), It is based on the availability of metal (iron Japan. and steel, copper, aluminium etc) and techni- D. Automobile Industry: cally skilled labour. I. Japan

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II. USA (Detroit: 30%) a wide area from Texas to North Carolina. 20 per cent of the country’s labour force is III. West Glerrary (45% of Europe) engaged in various industries of this region. Cotton textile, goods, aircrafts, aircraft IV.Canada (Windsor-Detroit of industry and petroleum refining are Canada) important industries. Charlotte, Columbia, V. Italy (Turin-Detroit of Italy, Milan) August, Atlanta, Knoxville, Chattanooga and Birmingham are important industrial E. Paper: First paper industry was estab- centers. lished in China. USA leads in produc- tion of fine paper from grasses (d) Pacific coast industrial region- Extends over the states of Washington, Oregon and News Print and Pulp: Production Ranking, California along the Pacific coast in the I Canada II USA III Japan. West. About 10% of the country’s labour force is engaged in manufacturing industries Industrial Regions of the World of this area. This is the smallest industrial Industrial regions emerge when a number region of the country. Los Angeles, San of industries locate close to each other and share Francisco, Seattle, San Diego are important the benefits of their closeness. Major industrial industrial centers. regions of the world are eastern North America, western and central Europe, Eastern Europe and Russia eastern Asia. Major industrial regions tend to be (a) Moscow-Tula Industrial Region-Moscow, located in the temperate areas, near sea ports Tula Gorky, Ivanovo and Yaroslava are the and especially near coal fields. chief industrial centres of the region. Iron- USA steel, heavy chemical, metallurgy, machine tools, textiles, automobiles etc. are the chief (a) New England Region- The region comprises industries. Ivanovo is known as the six states viz. Connecticut, Rhode Island, Manchester of Russia. This is the oldest and Massachusetts, Vermont, New Hampshire most important industrial center of the and Maine. The nucleus of this region is country. Boston. Major industries in the region are electrical machinery, textiles, engineering, (b) Ural Industrial Region: Stretches from and other metal industries- comprises 15% Magnitogorsk to Nizhnitaghil. The of the yearly output of the nation. Huge development owed much to the huge iron- capital, good communication, export ore deposits and good communication facilities, cheap and skilled labour and vast system. Magnitogorsk in one of the largest market are the chief advantages. Major steel centres of the world. Mining, metal industrial areas are Providence, Bedford, engineering and chemicals are the most New Haven and Springfield. important industries here. Out of eight big www.OnlineIAS.comindustrial centres Magnitogorsk, Sverdlovsk, (b) North-Eastern Region- In between Lake Chelyabinsk, Nizhnitaghil, Orsk, Molotar, Superior and Baltimore on Atlantic coast, are important. the region covers one tenth of the area and three-fourth of manufacturing industries (c) The Volga Region: The development of and half of the population. Pittsburgh and manufacturing activities is a new pheno- Cleveland districts known for iron and steel menon in this region. Tartar and Kyubushev industries; Akron for rubber manufacturing; oil fields are helping factors for New York, Philadelphia, Baltimore districts- concentration of industries here. Volgograd for textiles, steel, leather goods and chemical is the chief centre. industries; Detroit district (the greatest automobile centre of the world) for Europe

automobiles. (a) Ruhr Industrial Region is known as one of the (c) Southern Industrial Region- Extends over largest industrial region of Europe. The

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large reserve of Ruhr coal and Siegerland iron (b) The Kinki Region (Osaka-Kobe-Kyoto): ore and transportation route through Rhine Lies at the head of the Osaka Bay. Today were the major factor for concentration of this area produces about 30% of country’s pig number of industries with in an area of less and steel and 45% of its rolling mill output. than 50 miles from east to west and 25 mills The four principal groups of industries of from north to south. There are more than this district are metals, machines and tools, dozen of industrial cities with population textiles and chemicals. Ship-building, oil- varying from one lakh to five lakhs. Local refries and aircraft factories are also large coal deposit, in land waterways, local important.

skill are major factor for industrial (c) The North-Kyushu Region: The region conglomerations. covers large tracts of Hiroshima, Yamaguci, (b) Po valley of North Italy: Textile industries Okayama and Kitakyushu. The major including cotton, rayon and woolen are the centers of production in this region are most important industries of this plain. Tokuyama, Kokura, Yawata and Waka- Cotton textiles rank high in Italy’s export matsu.

trade. Turin, Lombardy, Pia Cenza, Emilia, China Bologna and Ravena are major industrial cultures. (a) Manchuria Industrial Region: The factors those were responsible for the growth of Japan this region is agricultural hinterland, good (a) Tokyo-Yokohama (Kwanto Plain): This transportation network, skilled labour, local region accounts for 30% of nation industrial capital and Japanese participation. Iron and output. Local hydel power, excellent rail steel, machines building, heavy engineering connections and abundant supply of labour industries were set up in Mukden, Harbin, are the other favorable factors. Tokyo, Fushun and Darten. Yakohama and Kawasaki are important centres.

Major Industrial Centres Country Major Industrial Centers Industries Britain Birmingham Iron & Steel, Heavy Machinery (Midland is the Coventry Automobile largest Industrial Burton-on-Trent Brewing (largest brewery town of

region centered Britain) at Birmingham) Stoke-on-Trent Pottery (Pottery capital of Britain) www.OnlineIAS.comNew Castle Shipbuilding Middlesborough Iron & Steel Bradford & Halifax Worsted textile Leeds Garments Shefield (World’s largest Cutlery and Iron & Steel

cutlery town) Manchester (Lancashire region) Cotton textile Liverpool & Birkenhead Shipbuilding Along Manchester Canal Heavy chemicals

Glasgow Hamilton Iron & Steel Motherwell Coatbridge

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Pot Glasgow Shipbuilding Belfast region (Main industrial Shipbuilding & region of Ireland) Linen industry France Lille Textiles Dunkirus Iron & Steel St. Etienne Armaments & Bicycle Limoges Pottery Lyon Silk making Marseilles Oil refineries Paris Champaque Aircraft & Transport Wine Lorrensar Iron & Steel Germany Frankfurt Railway engineering (Ruhr-Westphalia Mainz Leather, Brewing, Engineering region, served by Mannheim Chemical, electrical engineering, Rhine River, is the Ludwigshafen Iron & Steel. largest industrial region of Germany Hamburg Shipbuilding This industrial Munich Photographic equipment, Musical region is connected instrument to North sea by Stuttgart Automobile Dortmund-Ems Canal) Aachen Iron & Steel, Textile Leipzig Optical instrument Jena Zeiss Photographic equipment Dresden Porcelain Karl Marx Stadt Textiles Belgium Liege Iron & Steel, Guns, pistols & other firearms. Antwerp Diamond cutting Ghent Linen textiles

Luxemberg Luxemberg city Engineering Netherland www.OnlineIAS.comRotterdam Shipbuilding & marine engineering Amsterdam Diamond cutting Arnhem Tin smelting Sweden Goteborg Shipbuilding Stock- holm Shipbuilding Switzerland Zurich Engineering & Textiles Basel & Baden Engineering Denmark Copenhagen Dairy Italy Milan (main industrial region) Silk textile Turin (Detroit of Italy) Motor Car U.S.A. Boston Shipbuilding (Great Lake region is Pittsburg (Iron & Steel Iron & Steel the most important capital of the world)

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Industrial region) Akron World’s largest synthetic rubber & tyre making center Detroit Motor car & Aeroplane Pontiac Cars & its spare parts Flint Gary Iron & Steel Chicago Toledo Automobile Birmingham Iron & Steel Troy Garment Buffalo Iron Steel and Machinery (Also the largest Flour milling center of U.S.A) San Francisco (Silicon Valley) Oil refining, Shipbuilding, Computer technology Los Ange- les (Hollywood) Film & Aircrafts Canada Montreal Shipbuilding & Aircraft Toronto Engineering & Automobile Ottawa Paper Hamilton (Birmingham Iron & Steel and Engineering of Canada) Quebec Shipbuilding & Marine engineering Russia Moscow & Gorky Iron & Steel, Chemicals Magnitogorsk Iron & Steel & Oil refining Leningrad (St. Petersburg) Textile, Chemical, Paper Ukraine Krivoyrog Iron & Steel and Heavy Machinery Argentina Buenos Aires Shipbuilding China Shanghai Textile and Machinery Wuhan Textile, Machinery, Shipbuilding Iron & Steel Japan Nagoya (Detroit of Japan) Aircraft, Car, Machinery Osaka (Manchester of Japan) Shipbuil-ding, Textile, Iron & Steel Kyoto & Kobe Shipbuilding, Textile, Iron & Steel, Tokyo Shipbuilding, Engineering, and Textile Nagasaki www.OnlineIAS.comShipbuilding, Iron & Steel, Machinery

Points to Remember industrial units are centered at Detroit, Chicago, New York and Philadelphia. 1. Japan is the leading producer of shipbuilding industry. 4. The U.S.A. is the largest producer of planes; the other countries in the 2. Some of the important automobile industry of descending order are; U.S.S.R, U.K, the world are; Volkswagen and France, Canada, Italy, Australia and Mercedes in Germany, British Leyland in Japan. the U.K., Ford and Chrysler and General Motors of the U.S.A, Toyota and Mazda of 5. The chief producers of chemical industry Japan. are, U.S.A, West Germany, U.K and Japan.

3. The United States is the world's largest 6. The main petrochemical manufacturing locomotive producer; the prominent countries are the" U.S.A" , The European

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countries, West Germany, Netherlands, 16. Canada's main industrial region stretches Spain and Britain. from Lake Peninsula to Montreal.

7. Flour milling and meat packing are the 17. World's largest refinery is located at important industries of Chicago, Kansa "Sarnia", on the Huron shore. City, Omaha and Mid - West of the U.SA. 18. The Moscow -Gorki Region is the oldest 8. The "Ruhr-Westphalia" region of Germany and the greatest of Soviet industrial region is the largest industrial region. which includes the towns like Moscow, Gorki, Tula and Ivanova. 9. Leipzig is famous for optical instrument and Jena for Zeiss photographic equipment 19. The industrial region of Ukraine is chiefly . based on the rich Donetz or Donbas Coalfield and the "Krivoi Rog - Kerch" iron 10. The leading industries in Norway are field. marine engineering, shipbuilding, fish catching and the pulp and paper industries. 20. Some of the important industrial regions of Japan are: "Keihin region", Tokyo (noted 11. The leading industries of Denmark is for electrical engineering), Yokohama & centered at "Copenhagen" in "Zealand"; it (precision engineering, shipbuilding, oil is known for "dairying and agricultural" refining), Kawasaki (marine engineering), industries. Hansin region; Osaka (textile town), Kobe

12. Switzerland is highly industrialized and (shipbuilding), Kyoto (craft); Bay region; known for watch-making, engineering, Muroran (Iron steel,), Hiroshima (ship- building) etc. chemical and textile industries.

13. The "Lombardy plain" of Italy is the largest 21. "Keylong Valley" of Malaysia is the main industrial region. industrial region and contain major industrial cities of Milan, Turin, Genoa. 22. In Australia, the Coalfield of Sydney, iron

and steel industry of New Castle and port 14. In New England, Boston is known for Kembla, shipbuilding, chemical, air craft shipbuilding and shoe-making industry. industries of Melbourne; agricultural 15. "Pittsburg" of the U.S.A is the "iron and industries of Adelaide, Locomotive of steel capital" of the World. Brisbane are known

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ENERGY RESOURCES

Most of the world's energy resources are • Peat: from the sun's rays hitting earth. Some of that 1. Represents first stage in the formation of energy has been preserved as fossil energy; some coal from vegetation. is directly or indirectly useable; for example, via wind, hydro- or wave power. 2. Having high humidity content & therefore have no industrial value. Coal Distribution: Coal is the most abundant fossil fuel found in sedimentary source most of which has been formed Important areas famous for mining Donetsk during Carboniferous period. This was the fuel that basin (Ukraine), Kuznetsk basin (Russia), launched the industrial revolution and has contin- Karaganda (Kazakhstan) and Kansu-Achinsk ued to grow in use; China, which already has many basin (S. Siberia) are important and plays a very of the world's most polluted cities, is building about crucial role in the world economy. two coal-fired power plants every week. Coal is the 1. China: fastest growing fossil fuel and its large reserves would make it a popular candidate to meet the en- Datong (Shansi province), Ho-lin-Ho (Inner ergy demand of the global community, short of glo- Mongolia), Huainan & Huaibei, Yan Zhon bal warming concerns and other pollutants. (Shantung Peninsula) Pindingshan (Henan) and Kailnan (Hegei Province). Types of Coal: 2. USA: • Anthracite: The coal mining area of USA lies in the eastern 1. Carbon content - 90%, gives off little smoke part. The Appalachian coal region extends from and leaves little ash after being burnt. northwestern Pennsylvania to Alabama. Ken- 2. Very hard, shiny and free of impurities but tucky and Western Virginia are the major coal has very little reserves (57% of total coal) producing states in this region. Illinois, Utah, Wyoming, Colorado, Washington, Arizona and 3. Important reserves are in USA (Pennsylva- New Mexico are other important states. nia, 50%), former USSR (Donetz basin), Germany, U.K andwww.OnlineIAS.com Vietnam 3. Europe:

• Bituminous: Main belt extends from N.E. France to Po- land having Franco-Belgian Coalfields, 1. Carbon content - 70-90% gives smoky flame Campine-Limburg Coalfields, Ruhr, Saar, and leaves behind much ash. Silesia, Saxony and Pilsen.

2. Black & Shiny and gives tar (bitumen) 4. Australia: when heated. It is found in abundance (80% of total coal) Most of the coalmines lie in New South Wales. Some coal is mined in Queensland • Lignite (Brown Coal): and Western Australia.

1. Carbon content - 45-70% burns with high 5. Africa: smoky flames.

2. It is of much more recent origin & there- South Africa is most important country, fore contains higher proportion of humus. where important coal mines are located in Transvaal, Natal and Orange-Free state.

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6. India: The world's largest gas field is Qatar's off- shore North Field, estimated to have 25 trillion W.Bengal, Orissa, Bihar, M.P, Maharashtra. cubic metres of gas in place—enough to last more than 200 years at optimum production levels. Mineral Oil The second largest natural gas field is the South Pars Gas Field in Iranian waters in the Persian It is obtained from those decomposed tiny Gulf. Generally natural gas occurs together with marine creatures, minute plants and animals, mineral oil in the anticlines of sedimentary rocks. which were buried under the sediments about 10 to 20 crores years ago. It is generally found in Distribution: dome like structures of sedimentary rocks but all USA: Mid-Continental areas have largest sedimentary rocks may not have mineral oil. reserves (Texas, Louisiana, Oklahoma, Kan- Global distribution: sas), Rocky Mountains, New Mexico, Cali- fornia. USA: Appalachian Mt. Region (Oil was first drilled in Pennsylvania), Texas, Oklahoma, Former U.S.S.R: Western Siberia (Uregny Kansas, California, Louisiana and Wyoming. has world’s largest known reserves), North Alaska region have enormous reserves of Caucasus. both oil & gas but production in expensive Canada: Alberta, British Colombia due to cold climate and lack of transporta- tion. Most of the refineries of USA are lo- Others: North Sea (Europe), U.K, cated in N.E. USA due to high demand. Netherland, China.

Former USSR: Volga-Ural region (75% of total production), Caucasus region (20% of Nuclear Energy

total production) Mykope, Baku and Grozny of Georgia, Armenia and Azerbaijan), West- Nuclear power is power produced from con- ern Siberia. trolled nuclear reactions. Commercial plants in

West Asia: Southern Arabia (Dahran, use to date use nuclear fission reactions. Electric Ghawar), Kuwait (Burgan), Iran (Gachasaran, utility reactors heat water to produce steam, Masjid-e-Sulaiman), Iraq (Kirkuk, Mosul, which is then used to generate electricity. 14% Zubair, Rumeilla). Abadan (Iran) is the big- of the world's electricity came from nuclear gest refinery of West Asia. Basra is the most power, despite concerns about safety and radio- active waste management. important refining centre of Iraq.

Nuclear fusion reactions are widely believed South East Asia: Indonesia (central to be safer than fission and appear potentially Sumatra, Java & Kalimantan), Myanmar viable, though technically quite difficult. Fusion (Irrawady & Chindwin basin), Brunei. power has been under intense theoretical and experimental investigation for many years. Natural Gas www.OnlineIAS.comBoth fission and fusion appear promising for Natural gas primarily consists of methane. It is some space propulsion applications in the mid- found associated with fossil fuels, in coal beds, as to distant-future, using low thrust for long du- methane clathrates, and is created by methanogenic rations to achieve high mission velocities. organisms in marshes, bogs, and landfills. It is an important fuel source, a major feedstock for fertiliz- On June 27, 1954, the USSR's Obninsk ers, and a potent greenhouse gas. Nuclear Power Plant became the world's first nuclear power plant to generate electricity, and The world's largest proven gas reserves are produced around 5 megawatts of electric power. located in Russia. Russia is also the world's larg- est natural gas producer, through the Gazprom The world's first commercial nuclear power Company. Major proven resources are Russia, station, Calder Hall in Sellafield, England was Iran, Qatar, Saudi Arabia and United Arab opened in 1956 with an initial capacity of 50 MW Emirates. (later 200 MW). The first commercial nuclear

www.OnlineIAS.com N. Kalyana Chakravarthy 117 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] generator to become operational in the United through use of the gravitational force of falling States was the Shipping port Reactor. or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric com- Many countries remain active in devel- plex is constructed, the project produces no di- oping nuclear power, including China, In- rect waste, and has a considerably lower output dia, Japan and Pakistan, all actively devel- level of the greenhouse gas carbon dioxide (CO2) oping both fast and thermal technology, than fossil fuel powered energy plants. World- South Korea and the United States, devel- wide, an installed capacity of 777 GWe (Giga oping thermal technology only, and South watt - Electric) supplied 2998 TWh (tera watt Africa and China, developing versions of the hours) of hydroelectricity in 2006. This was Pebble Bed Modular Reactor (PBMR). Sev- around 20% of the world's electricity and about eral EU member states actively pursue 88% of electricity from renewable sources. nuclear programs, while some other mem- ber states continue to have a ban for the Distribution: nuclear energy use. In the Scottish Highlands of United Kingdom, Uranium and thorium are major sources there are examples at Kinlochleven and Lochaber, which are radioactive minerals having immense constructed during the early years of the 20th capacity to generate energy through nuclear fis- century. The Grand Coulee Dam, switched to sion. support Alcoa aluminum in Bellingham, Wash- ington, United States for irrigation and power (in 1. Uranium: addition to aluminum power). Two primary ores of Uranium; Pitchblende In Surinam, the Brokopondo Reservoir was (Uranium content 50 to 80%) and Uraninite (Uranium content 65 to 80%) constructed to provide electricity for the Alcoa aluminium industry. New Zealand's Manapouri Distribution: Power Station was constructed to supply elec-

t Tiwai Point. Canada: Uranium city (on northern bank of tricity to the aluminium smelter a lake Athabasca), Port Radium (Lake Great Bear). As of 2007 the Kárahnjúkar Hydropower Project in Iceland remains controversial. • USA: Colorado plateau has rich deposits. Failure Hazard: • South Africa (Witwatersrand), Dam failures have been some of the largest • Australia (Mary-Kathleen), man-made disasters. Also, good design and con- • Europe (Central Massif), and struction are not an adequate guarantee of safety.

• Japan (Tobo) For example, the Banqiao Dam failure in 2. Thorium: Southern China resulted in the deaths of 171,000 people and left millions homeless. Also, the cre- Important Ores: (i) Monazite (ii) Thorianite ation of a dam in a geologically inappropriate (iii) Allnite www.OnlineIAS.comlocation may cause disasters like that of Vajont Dam in Italy, where 2000 people died in 1963. Distribution: Smaller dams and micro hydro facilities cre- Monazite: Malabar Coast of Kerala & T.N. ate less risk, but can form continuing hazards (India), Brazil, Australia, Malaysia, and USA, even after they have been decommissioned. For Srilanka. example, the Kelly Barnes small hydroelectric Thorianite: Sri Lanka (Ratnapur dist.) dam failed in 1967, causing deaths with the Toccoa Flood, ten years after its power plant was Allnite: Rajasthan & Andhra Pradesh (In- decommissioned in 1957. dia) Famous Hydel Projects of the world: Hydel Energy USA: Colorado River – (i) Davis (ii) Parker (iii) Hydroelectricity is electricity generated by Boulder (Hoover) dams. hydropower, i.e., the production of power

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Colombia River – (i) Grand Coolie dam (ii) Parana River – Itiapu Project. Bonneville dam Ghana (Africa) – Volta River – Akosombo Tennessee River – (i) Wheeler (ii) Wilson dam

(iii) Norris (iv) Chickamauga Dam. Egypt – Nile River – Aswan dam. Mississippi River – (i) St. Anthony fall project. Uganda – Owen Falls project Sacramento River (California) – Shasta dam. China: Huangnihe River – Lubuge Project. Africa: Zambezi River – Victoria Falls – Shasta dam. Three go rges Dam of china is the largest hydel power project in the world. Sudan – Nile River – Senar dam.

Zaire or Congo River – Stanley dam

Country Annual Hydroelectricity“ Installed“ Percent of“

Production (TWh) Capacity (GWe) total electricity China 585.2 171.52 17.18 Canada 369.5 88.974 61.12 Brazil 363.8 69.080 85.56 United States 250.6 79.511 5.74 Russia 167.0 45.000 17.64 Norway 140.5 27.528 98.25 India 115.6 33.600 15.80

Sweden has maximum energy from oil but lustrated in Figure 2, and also described briefly also has the largest share of her energy of HEP hereunder with respect to the northern hemi- in the world. Netherlands has maximum energy sphere, with the understanding that the same from natural gas. 80% of oil & 90% of coal is conditions apply to the corresponding belts in found north of 20° n latitude while 80% of hydel the southern hemisphere: power energy potential is south of 20° n latitude. (I) Most Favourable belt

Solar Energy This belt, lying between latitudes 15°N, and www.OnlineIAS.com 35°N, embraces the regions that are naturally It is common knowledge that solar radiation is endowed with the most favourable conditions unevenly distributed, and that it varies in inten- sity for solar energy applications. These semi-arid from one geographic location to another de- regions are characterized by having the greatest pending upon the latitude, season, and time of day. amount of solar radiation, more than 90% of Until recently, valid records for solar radiation have which comes as direct radiation because of the been very scanty in the vast majority of the devel- limited cloud coverage and rainfall (less than 250 oping countries. In the absence of such useful in- mm per year). formation as a guide for the proper exploitation of solar energy, only general hints can be offered re- (II) Moderately Favourable belt garding the geographic areas with favourable con- ditions for solar energy applications. This belt lies between the equator and lati- tude 15°N, and is the next most favourable re- For convenience and simplicity, the geo- gion for the purpose previously mentioned. Be- graphic distribution of total solar radiation on a cause the humidity is high, and cloud cover is global scale is divided in terms of intensity into frequent, the proportion of scattered radiation four broad belts around the earth. These are il- is quite high. There is a total of about 2,500 hours

www.OnlineIAS.com N. Kalyana Chakravarthy 119 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected] of sunshine per year. The solar intensity is al- (IV)Least Favourable belt most uniform throughout the year as the sea- sonal variations are only slight. The regions in this belt lie beyond latitude 45°N. They include the USSR, and the greater (III) Less Favourable belt parts of northern Europe and North America.

Here, about half of the total radiation is dif- This belt lies between latitude 35°N and fuse radiation, with a higher proportion in 45°N. Although the average solar intensity is winter than in summer primarily because of roughly about the same as for the other two belts, the rather frequent and extensive cloud cov- there are marked seasonal variations in both ra- erage. diation intensity and daylight hours. During the winter months solar radiation is relatively lower than in the rest of the year.

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TRANSPORT

Transportation means movement of goods (h) Cape Cairo railway- It runs from Cape and passengers from one place to another. It Town to Cairo in Egypt. plays a vital role in production and distribution and hence is called the life blood of commerce. (i) Orient Express railway- It runs from Paris to Constantinople in Turkey. The means of transport are grouped under three heads (i) land transport (ii) water trans- (j) Trans-Andean railway- It runs from port (iii) air transport. Valparaiso in Chile to Buenos Aires in Ar- gentina.

Land Transport (k) Australian transcontinental railway- It runs from Perth to Sydney in Australia.

1. Road Transport

Trans Continental Railways Routes They are the most universal form of trans- port. It was only in the eighteenth century that The Iran Siberian Railway: It connects roads were systematically built and surfaced. Leningrad and Moscow in the west to Vladivostok Highways have been constructed to facilitate in the East. Length of this route is 5600 miles. speedy transportation of goods and passengers. The Pan-American Highway, Brasilia - Belem The Canadian Pacific Route: It Connects road etc are some of the important highways. Halifax (East of Canada to Vancouver in west the U.S.A has the largest length of roadways and also length of 7500 kms. The route has been con- nected to Lake Superior via Winnipeg. the largest number of automobiles. 2. Railway The Australian Transcontinental Railway: It run from Fremantle (Perth) to Sydney via The first railway was opened between Stock- Kalgoorlie, Adelaide, Canberra and Melbourne. ton and Darlington in England in 1825. The main 3. Pipelines railway routes of the world are as under:

(a) Northern trans-continental railway- It runs Pipelines are becoming an increasingly im- from Seattle to New York in U.S.A. portant form of transport. They generally trans- port petroleum and natural gas. The most fa- (b) Central transcontinental railway- It runs mous pipeline in U.S.A is the ‘big inch pipeline’ from San Francisco to New York. which transports oil from Gulf of Mexico to the (c) Southern transcontinentalwww.OnlineIAS.com railway- It runs north-eastern parts. The longest pipeline of the from Los Angeles to New York. world is called ‘Tapeline’.

(d) Canadian- Pacific railway- It runs from Water Transport Halifax to Vancouver in Canada.

(e) Canadian national railway - It runs from Water transport can be divided into: (i) in- Saint John to Vancouver. land waterways and (ii) Ocean transport.

(f) Trans-Siberian railway - It is the longest Inland Waterways rail route of the world and runs from Leningrad to Vladivostok. Inland waterways consist mainly of navi- gable rivers and canals. The largest rivers of the (g) Trans Caucasian railway- It runs from world like Amazon, Yangtze Kiang, Mississippi’ Batum to Kursk. Rhine, Volga, St Lawrence etc are navigable.

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Ocean Transport The Cape of Good Hope Route: It connects Western African Countries, South Africa, Aus- The main oceanic routes of the world are: tralia and New Zealand.

1. North Atlantic route: It is the busiest trade route of the world and connects ports of Important Canals of World

Western Europe with ports on the eastern Canal link coast of North America. Suez Canal Mediterranean Sea and 2. The panama route: It connects the ports of Red sea the pacific with the ports in the Atlantic ocean. Panama Canal Pacific Ocean and 3. The Mediterranean:Suez-Asiatic route. It Atlantic Ocean connects the western European countries with the Asian countries. Kiel Canal North Sea and Baltic Sea

4. The cape route: It connects the western Soo canal Lake Superior and Lake and southern sections of Africa with west- Huron ern Europe. Manchester canal Manchester and isthmus. 5. South Atlantic route: It links Europe with the Caribbean islands and the eastern coun- North Sea canal North Sea and Amsterdam tries of south America. New waterway canal North Sea and Rotterdam 6. The pacific route: It connects the western Stalin canal Rostor and Stalingrad seaboard of North America with eastern part of Asia. Gota Canal Stockholm and Guttenberg

Mitteland canal Ems, Weser and Elbe rivers Important Waterways and Sea Routes Dortmund-Ems canal Rhine and Bremen The Mediterranean or Suez- Asiatic Route: Considered as the line of Britain, this route con- Ludwig canal Main and Rhine rivers nects East Africa, South West Asia, Far East via Mediterranean Sea and Arabian Sea. Air Transport

The Panama Canal or West Indies: Cen- tral American Route: Considered as the Gate- Air routes can be broadly classified into (i) way to the Pacific, this route has facilitated Intercontinental (ii) Continental (iii) National and trade in the West Indies islands and the pacific (iv) Regional air routes. states of North, Central and South America U.S.A has the largest number of Airports. especially the Andean States Panama and Co- London’s Heathrow airport is the busiest airport lon are the ports on two sides. in the world. The main national airways include The South Atlanticwww.OnlineIAS.com Route: It connects Eu- British airway, Lufthansa (Germany), KLM ropean countries with Brazil, Argentina and (Dutch), Air Italia, Air France, SAS (Norway, Uruguay. Sweden, Denmark), Qantas (Australia), Aeroflot (Russia), Japan airlines and United air- The North Pacific Oceanic Route: Western lines, TWA, Pan-American airlines (all USA) etc. coast towns of United States are connected with Tokyo, Kohima etc. Points To Remember The South Pacific Oceanic Route: Austra- lia, New Zealand, North America and Western 1. “Autobahn”, a 3,200 km long highway of Europe are connected. Germany was built by Hitler

The North Atlantic Route: It connect East- 2. The first public railways was opened be- ern coast of United States to Western Europe and tween Stockholm and Darlington in north- is one of the busiest routes of the world. ern England in 1825.

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3. The greatest railways densities are found in 10. The Ludwig Canal of Germany links the the industrial region of the “Western Europe” Rhine to the Danube and allows water born in which “Belgium” has the greatest density. traffic from Black sea to the Mediterranean Sea through the Rhone-Rhine canal. 4. The Trans - Siberian railway of Asia, runs from Leningrad to Moscow, is the most 11. The “Saint Lawrence Waterways” of North important east - west link. It has the con- America is the most important; it is ice - necting links with Odessa in Ukraine, Baku in bound for three to four months in a year.

the Caucasus, Tashkent in Russia, Ulan Bator 12. The Mediterranean Suez - Asiatic route in Mongolia, Shenyang in Manchu- ria and which links Europe with the far east is Beijing in China. considered as the life - line of Britain be- 5. “India” has the densest railway network in Asia. cause oil supplies from middle - east and tropical raw materials and food stuff from the 6. It is possible to travel entirely by river and Asiatic colonies comes through the Suez. canals from the Mediterranean sea to the English channel or from Rhine to the At- 13. The “Panama Canal” which came into lantic ocean. existence in 1913 is the gateway to the Pacific. It has facilitated the trade in the West 7. The “Mitteland Canal” joins the three Indian islands and the Pacific states of major rivers of Ems, Weser and Elbe North, Central and South America.

8. The “Kiel Canal” links the Elbe estuary to 14. The first regular air service was started in the Baltic Sea. 1919 between Londo n and Paris.

9. Dortmund -Ems canal runs north-south and 15. The “Commonwealth Air Route” passes links the Rhine with ports of Bremen and through London, Rome, Kuwait, Bahrain, Emden. Karachi, Bombay, Colombo, Kuala Lumpur and Singapore.

www.OnlineIAS.com

www.OnlineIAS.com N. Kalyana Chakravarthy 123 +91-9246365622 Vidyarthi - Bharat Ki Shakti [email protected]

www.OnlineIAS.com

www.OnlineIAS.com N. Kalyana Chakravarthy 124