CHAPTER NO.4 LANDFORMS

CHAPTER NO.4 LANDFORMS

 

Plains, Mountains and Plateaus :In order to make a systematic study and also for the sake of convenience, Geographers have divided the landforms into three orders of relief. A brief description of the first, second and third orders of relief has been given below:-

 

 

We shall study relief features of Second order in detail.

Mountains : Mountains are significants relief features of the second order on the Earth’s surface.

 

1. Mountain Ridge : A Mountain ridge is a system of long, narrow and high hills. Generally, the slope of one side of a ridge is steep while the other side is of moderate slope but a ridge may also have symmetrical slopes on both the sides.

 

2. Mountain Range : A Mountain range is asystem of mountains & hills having several ridges, Peaks and summits and valleys. Infact, a mountain range stretches in a linear manner. In other words, a mountain range represent a long but narrow strip of mountains and hills. All of the hills of a mountain range are of the same age but there are structural

variations in different members of the range.

 

3. Mountain System : A Mountain chain consists of several parallel long and narrow mountains of different periods. Sometimes, the mountain ranges are separated by flat uplands or plateaus while Mountain System consists of different mountain ranges of the same

period. Different Mountain ranges are separated by valleys.

 

4. Mountain Group & Cordillera : A mountain group consists of several unsystematic patterns of different mountain systems. Cordillera consists of several mountain groups and systems. Infect, cordillerais a community of mountains having different ridges, ranges, mountain chains and mountain systems. The mountainous system of the western part of North America is the best example of a Cordillera.

 

Classification of Mountains

1. On the Basis of Height :

(a) Low Mountains; height ranges between 700 to 1000 meters.

(b) Rough mountains (less height) — 1000 to 1500 meters.

(c) Rugged Mountains (medium height)- 1500 to 2000 meters.

(d) High Mountains; height above 2000 meters.

 

2. On the Basis of location :

Continental Mountains.

(a) Coastal Mountains: Applachian, Rockies, Alpine mountain chains, Western and Eastern Ghats of India etc.

(b) — Inland Mountains: Himalayas, Aravallies Urals

(c) Coastal Mountains: Mauna kea, Hawaii Islands.

(d) Oceanic Mountain: Most of the oceanic mountains are below water suface. E.g. Mauna Kea (Hawaii Islands)

 

3. On the basis of Origin :

(a) Original or Tectonic Mountains : These Mountains are formed due to tectonic forces e.g compressive and tensile forces motored by endogenetic forces coming from deep with in the earth. These Mountains are further divided into 4 types on the basic of orogenetic forces responsible for the origin of a particular type of  mountarns.

 

(b) Circum erosional or relict mountains : Such mountains came into from because of erosion, millions of years back. In India, example of such mountains is; Vindhayachal range, Aravallies, Satpura, Eastern Ghats,Western Ghats etc.

 

 

4.On the basis of period of origin :

(a) Pre-Cambrian mountains :- These mountains are 4.6 billion years old; examples, Laurentian, Algoman and Kilarean mountains (Allin North America).

 

(b) Caledonian mountains :- Formed during Silurian period and devoman period, 44 to 40 crore years back. examples; Taconic mountains of the Applechian system, mountains of Scottland, Lreland and Scandinavia

(Europe) Brazilies of South America, Aravallis, Mahadeo, Satpura etc. of

India.

 

(c) Hercynian Mountains :- Mountains formed during Permian and permocarboniferous periods, examples mountains of Iberian Peninsula,

Spanish Messeta and Brittany of France, Tarim basin etc.Explanation and Details of Some more types of mountains

 

(d) Alpine Mountains :- Mountains formed during tertiary period, some

6 crore years to 25 lakh years old; examples; Rockies (North America)

Andies (South America), Alpine System of Europe (Main Alps,Carpathians, Pyrehess Balkans, Cancasus), Atlas Mountains (N.W.Africa) Himalyas and Mountains coming out of Pamir Knot of Asia

(Taurus, Pountic, Zagros, Elburz, Kunlun etc.)

 

Block Mountains : Block mountains, also known as faultblock mountains, are the result of faulting caused by tensile and compressive forces motored by endogenetic forces emerging from within the Earth.Block mountains represent the upstanding parts of the grounds between

two faults on either sides of anft valley or a graben. Essentially, block

mountains are formed due to faulting in the ground surface.

Represented by (1) fault scrap and one gentle side and (11) lifted block mountains represent real horst and are characteriased by flattened summit of tabular shape and very steep sides slopes represented by two boundary fault scraps. Block mountains are also called Horst mountains.Sierra Navada mountains of Cahfornia (USA) is considered to be the

most extensive block mountain of the world. Salt range of Pakistan,Rhine rift valley in Europe are other examples of Block mountains.

 

Folded Mountains :- Folded mountains are formed due to folding of crustal rocks by compressive forces generated by endogenetic forces emerging from within the Earth. These are highest and most extensive mountains of the world and are found in all the continents. They are

generally found along the margins of the continents either in North South

direction or east-west direction. Rockies, Andes, Alps, Himalayas, Atlas

etc. are the examples of folded mountains. Folded mountains are classified on various bases a follows:-

 

(a) Simple folded mountains :- Such mountains are characterised by well developed system of anticlines and synclines wherein folds are arranged in wave-like patterns. These mountains have open and relatively simple folds anticline.

 

(b) Complex folded mountains :- These mountains represent very complex structure of intensely compressed folds such as ‘nappe’ in fact,complex folded mountains are formed due to the formation of recumbent folds caused by powerful compressive forces.

 

Folded mountains are also classified into two categories; (i) Young folded mountains for example Alps in Europe and Himalayas in Indian sub continent and (41) Mature folded moutains for example Aravallies,Vindheyachal etc.

 

Geosynclines Meaning:- The geological history of the continents and ocean basins denotes the fact that in beginning our globe was characterised by two important features

(1) Rigid Masses and

(ii)geosynclines.

 

Rigid masses representing the ancient nuclli of the present containts, have remained stable for considerably longer period of time.These rigid masses are supposed to have been surrounded by mobile zones of water characterised by extensive sedimentation. These mobile

zones of water have been termed ‘geosynclines' which have now been

converted by compressive forces into folded mountains. The geosynclines are long but narrow and shallow water depressions characterized by sedimentation and subsidence.

 

Orogeny ,

Orogeny refers to force and events leading to a large structural

deformation of the Earth’s lithosphere which constitute mountains ranges. Most orogenic belts arises on the sites of Geosynclines and the resulting mountains therefore consist of sediments and volcanic rocks deformed and metamorphosed to a greater or lesser extent according to their position and depth in the orogenic belts.

 

Generally speaking, high-standing mountain masses (other than volcanic mountains) are elevated by one of two basic tectonic processes:Compression and extension.

 

Compressional tectonic activity- “squeezing together’ or “crushing’’-

acts at convergent plate boundaries; extensional tectonic activity —

“Pulling apart’ — occurs where oceanic plate is undergoing break-up into

fragments.

 

Continental Drift and Plate Tectonics

Continental Drift Theory

 

The theory of continental drift is an attempt to explain the present

arrangement of continents and ocean basins. The idea of continental drift

is very old as Abraham Ortelius in 1596. The concept was independently and more fully developed by Alfred Wegner, a German meteorologist and geophysicist, in his book “Origin of Continents and Oceans’ published in 1915. In his theory it is presumed that in the geological past all the continents were ‘united’ together. This Parent continent was known as Pangea (Pan = All + gea = Earth). The Pangea was surrounded by a huge sea ‘Panthalassa (Pan = All + thalassa = ocean) representing Primaeval

Pacific Ocean. Wegner hypothesized that the surface of super continent (Pangea) broke up to form: 1. Lurasia (North America, Greenland and whole Eurasia, North of Indian sub-continent) and (11) The Gondwana Land (S. America, Africa, Madagascar). Now Malagasy, Peninsular

India, Australia and Antarctica, in the carboniferous period about 300 million (30 crore) years back. He opined that continents are made up of SIAL (Sillicon and Aluminium) and ocean basins of SIMA (Sillicon and Magnesium).

 

Wegnar developed this concept while trying to explain the climate of the

past. The puzzling questions in his mind were:

 

(1) Why should tropical ferns (vegetation) have grown in temperate

countries like England, Germany, France and Greenland ?

 

(2) Why the Glaciers have covered parts of Brazil, Peninsular India,Australia and Congo Basin? These climate changes may be explainedin two ways:

 

(a) If the continents reclaimed stationery at their places, the climate zones might have shifted from one region to another.

 

(b) If the climatic zones remained stationery, the landmasses might have

been displaced and drifted. Since climatic zones are controlled by the

heat from the sun, their shift cannot be explained. It is more probable that

the landmass have changed their position. According to Wegner, the

continents drifted in two directions: towards Equator and towards West.

Evidence in support of Continental Drift

 

(1) Geographical similarities in opposing coast of the Atlantic Ocean.

‘Jigsaw-fit’ of the opposing coasts of Adantic ocean.

 

(2) Fossils of glossopteris (a fern-likeplant) have been found in rocks of

the same age from South America, India and Australia. Fossils of Lystrosaurus (Lizard type animal) have been found in South Africa,India, and Antarctica. There is no way that such huge animals travelled across oceans if lands were not adjoining earlier.

 

(3) Folded Mountain ranges at Cape of Good Hope and rocks of Buenos Aires (Argentina) resemble.Wegner was however, criticized for failing to explain the forces that would permit continents to plough through the ocean of rocks. Wegner died in Greenland in 1930. The idea of continental drift got revived in

1950s and 1960s. In 1940, seismologist Hugo Benioff plotted the location of deep earthquakes at the edges of Pacific ocean. He plotted 30,000 earthquakes and established the ring of fire. The Continental Drift Theory became basis of Plate Tectonic Theory.

 

Before we leave this page are you able to answer :-

1. What is Continental Drift Theory ?

2. Describe observations Wegner used to support Continental Drift.

3. Discuss why the hypothesis was not widely accepted?

 

Plate Tectonic Theory

Plate Tectonic Theory is acomprehensive theory which offers explanations for various relief features and tectonic events viz. mountain building, folding and faulting, continental drift, vulcanicity, seismic events (earthquakes) etc.Base of the Theory

The rigid lithospheric slabs or rigid and solid landmasses having athicknes of about 100 km composed of Earth’s crust and some portion of upper mantle are technically called ‘Plates’. The term ‘plate’ was first used by Canadian Geologist John Tuzo Wilson in 1965. The whole mechanism of the evolution, nature and motion and resultant reactions of

plates is called ‘Plate Tectonics’. Plate tectonic theory is a great

scientific achievement of the decade of 1960s is based on two major scientific evidences e.g. (i) evidence of Palaeo magnetism and (i1)evidences of sea floor spreading six major and 20 minor plates have been identified so far.

 

Mckenzie and Parker discussed in detail the mechanism of plate motions

on the basis of Euler’s Geometrical Theorem in 1967. Prof. Hary Hess

(1960) elaborated the mechanism of Plate movement on the basis of the

evidences of sea floor spreading. W.J. Morgan and Le Pichon elaborated

the various aspects of plate tectonics in 1968.

 

Three types of Plate Boundries on the origin of continents and ocean basins have been identified e.g. (4) Constructive plate boundaries

(ii) Destructive plate boundaries (111) Conservative plate boundaries.

 

1. Constructive Plate Boundries are also called as ‘divergent plate boundary’, spreading boundary, or accreting plate boundary,represent zones of divergence along the mid oceanic ridges and are

characterised by continuous addition (accretion) of materials as there is

constant upwelling of motion materials (basaltic lava) from below the mid-oceanic ridges. These basaltc lavas are cooled and solidified and are added to the trailing margins of the divergent plates and thus new oceanic crust is

continously formed. In fact,oceanic plates split apart along the mid-oceanic ndges and moves in opposite directions and thus transform faults are formed.

 

2. Destructive Plate Boundaries are also known as “Cosuming Plate Boundaries’ or ‘Convergent Plate Boundary’ are those where two plates collide against each other and the leading edge of one plate having relatively lighter material overrides the other plate and the overridden plate boundary of relative denser material ts subducted or thrust into the upper mantle and thus a part of the crsut in lost in the mental. This is why convergent plate margins are called destructive margins, Collision zone,

subduction zone and ‘Benioff Zone’. See Fig.

 

3. Conservative Plate Boundaries are also known as Sheer Plate Boundaries, and Transform Boundaries. Transform faults are those where two plates slip past each other without any collision along the transform fault and thus crust is neither created nor destroyed.

Mechanism of the Theory

According to Plate Tectonic Theory, mountains are formed due to collision of two convergent plates. Mountains are always formed along 

the destructive plate boundaries. It is obvious that the process of mountain buiding is associated with destructive plate boundaries of two convergent plates. The Plate Tectonic Theory envisages the formation of mountains due to compression of sediments caused by the collision of twoconvergent plate boundaries. Two plates moving together under the impact of thermal convective currents collide against each other and the plate boundary having relatively denser material is subducted under the other plate boundary of relatively lghter materials. This subduction zone is also called Benioff Zone. The subduction of plate boundaries

causes lateral compressive force which

ultimately squeezes and folds the

sediments and material of the margins at

the plates and thus mountains are formed.

 

Rockie mountains find their origin in

colliston of American and Pacific Plates

while Andies again are result of same

collision. Himalayas rose out of collision of Indo-Australian plate against that of Eurasian. Indian plate is stillin process of insertion under Eurasian plate and Himalayas are rising.

 

 

Mountains for Mankind :

 

1. Mountain region has covered 27% part of total land area of the Earth

while it houses 22% population of the world.

 

2. Mountains fulfill various necessities of non-mountai nous dwellers like fresh water which flows down mountains through rapids, falls and rivers. Hydroelectricity, Wood, Medicinal plants, wild ani mals/insects, fruits and various other products which are available in and through forests only.

 

3. Mountainous ecology is home for many forest animals, insects and birds which do not find their habitat other than mountainous forests.Dense forests on mountains help in balancing healthy ecosystem and biological diversity.

 

4. Mountains are source of attraction for tourism related activities. Big

number of people visit mountainous regions as tourists. Cultural and

religion heritage in India provides spiritual touch to mountainous centres since times immemorial. Many religion centres have been set upin vallies of Himalayas particularly.

 

5. Mountains have their lasting effect over climate of any region. In India, the Himalayas contribute very  importantly for rainfall not only

through Monsoonic winds but through cyclones also. Uncontestidly the rainfallis lifeline for agriculture in our nation.

 

Plateaus

Plateau is an elevated tract of relatively flat land, usually limited on at least one side by a steep slope falling abruptly to lower land, it may also be deli mited in places by abrupt slopes rising to residual mountains or

mountain ranges, as in the Tibetan Plateau, where it occurs as an

intermontane Plateau. The term is also used to refer to a structural

surface such as Meseta of Spain, in which case it is a tectonic Plateau. The

surface of Plateaus may be plain-like in quality, very flat, rolling or hilly,

or may be so dissected by streams and Glaciers that it is difficult to

recognise their original Plateau Characterstics. Great Plateaus and some

of the small ones are closely associated with mountains and are primarily

the products of diastrophism or volcanism. Many small Plateaus are

merely remmants, left standing above the surrounding land as a result of

erosion.

 

Diastrophism & Classification of Plateaus :

The large scale deformation of the Earth’s crust which produces Continents, Ocean Basins and Mountain ranges, etc. ts known as diastrophism. Since their uplifts they have been modified by various agents of erosion and in many cases by volcanism and minor Earth

movements. For convenience and on the bases of geographical relief formation, weather and development plateus may be classified as under :

 

1. Intermontane Plateaus

These include the highest, largest and in many respect most complex Plateaus of the world. Their surfaces show an extraordinary variety of topographic features. Some plateaus of this type are as under :

 

(i) Plateau of Tibet : The great highland of Tibet, called the Heart of

Asia, is the largest and highest Plateau ever known. Its areais between

7 to 8 lakh square miles and average elevation is more than 4500 meters

(14800 feet) with many parts rising to more than 5538 meters (1 8000 feet) above the sea level. It is bounded in the North by the Kunlun mountains, and in the south by the mighty Himalayas.

 

(ii) The Plateau of Bolivia and Peru

This is another excellent example of an intermontane Plateau which lies largely in Bolivia at an average elevation of more than 1350 meters above the sea sevel. There is abundant evidence that highland was uplifted during tertiary period when the Andies were formed. Great Andies mountain ranges surround the Plateau. At present, the main part

of the Plateau has no exterior drainage.

 

(iii) The Mexican Plateau

The Mexican Plateau stands between the eastern and western Sierra Madre Mountains. The surface of the Plateau slopes gently northward from near Mexico City with elevation, 1800 meters to 2300 meters of Large parts of this Plateau are very dry. Moreover, several Volcanic

Mountains stand on the south end of the Plateau near Mexico city.

 

2. Piedmont or Border Plateaus

Many Plateaus border mountain ranges and owe their present position to the same uplifts that raised the mountains. Piedmont Plateau is an example of border Plateaus. This Plateau is a strip of land that stand between the Atlantic Coastal Plains and the Appalachian Mountains. Its eastern side is marked by a more or less definite fall-line where the gradient of the rivers is steepest. On the west it terminates against the

mountains of the Blue ridgde. Patagoniais another example of such

plateaus in South America.

3. Domed Plateaus

The plateau of Ozark (USA) is a good example of domed plateau. Ozark Plateaus was uplifted by folding and faulting into a broad dome some 65,000 square km (40,000 sq. miles)in area. Entrenched meanders are significant features of many of the upland streams.

 

4. Volcanic Plateaus

Volcanoes also forms several varieties of Plateaus, built by the Lava flow.

Smaller, degraded Plateaus are formed by the resistant lava caps that protect the land from erosion and maintain its high elevation after the surrounding land has been worm away. Deccan Plateau in Indiais the best example of Volcanic Plateau while other good example is North Island, Volcanic Plateauin New Zeland.

 

5. Erosional Plateaus: Such Plateaus are formed particularly in semi-arid regions where streams it cut away portions of high mountain, leaving broad, nearly flat inter-valley highlands. Allegeny Plateau area in western and central New York and Cumberland. Plateau, the part of  Appalachian Plateau region in United States of America are examples of Erosional Plateaus.

 

Life History of Plateaus :The life history of Plateaus, like that of any other highland, depends upon a number of factors, of which diastrophism and climate are the most important. Assuming that the land stands still, Plateaus of humid regions will pass through the typical successive strages of a cycle of

erosion and will be reduced to Peneplains. Plateaus of Arid regions,

although worn away much more slowly, must eventually go through the

various stages of an arid cycle of erosion. The ultimate result will be

dissection and loss of all the original characteristics. Plateaus on coasts

are subject to the attack of both sub-aerial agents and of waves and

currents.

 

Importance of Plateaus for Mankind :

 

1. Plateaus keep mineral wealth lapped in them. Various minerals like Gold, Iron, Copper, Diamond, Maganeese, Mica etc. are solid base of industrial development of any nation.

 

2. Plateaus are have more plain regions as compared to pure mountainous regions which helps in development of means of

transport. Rail and road transport is lesser costly in plateau regions

as compared to mountainous regions.

 

3. Plateau regions support abrupt slops which are beneficial for setting

up hydoelectrical centres.

 

4, Plateaus are instrumental in making effect over climate. As an example; Tibet plateau divides western Jet Stream in two parts while in summer helps in creating low pressure which results into

attraction for Monsoons in Indian Sub-contiennt.

 

5. Plateau regions are beneficial for its own types of agricultural products. Deccan Plateau in India provides black soil which is unmatchable for production of Cotton and Sugarcane.

 

PLAINS

Plain is an extensive tract of flat and or a gently undulating terrain without prominent hills or depressions. Plains, the lowlands of the Earth,may be very flat, moderately rolling, or even hilly. They are formed both by internal forces of the Earth and by external processes of aggradation and degradation. They range in size from very small to a very large areas.

 

The great centres of population of the world are on plains. For more people live on plains than on Plateaus and mountains combines.Development of means of communications and transportation facilities is easier in the plains.

 

Origin of Plains:

Like other major reef features, Plains are best classified according to their origin. On the basis of their origin the plains may be classified under following categories:

 

1. Diastrophic Plains

2. Peneptains,

3. Flood Plains,

4. Delta Plains.

5.Glaciated Plains and

6 Aeolian Plains.

 

(1) Diastrophic Plains: Nearly all the great plains of the world are regions that were once submerged by  epicontinental seas. Some were

uplifted long ago and have been modified by many agents of gradation.Others have been raised above sea level in comparatively recent times and have had correspondingly shorter and less complex life history.

 

The great plains of U.S.A. are the example of plains formed due to

upliftment or emergence of submerged landmasses under epicontinental

seas. The Great Plains are bordered by Rockies in the west, by central

lowlands (Mississippi-Missouri Plains) in the east and by Rio-Grande River in the south. The plain further extend northward to Canada. It is believed that the great plains remained under water in cretaceous period for a fairly long period and hence horizontal thick beds of Marine sediments were deposited. The submerged landmass began to rise due to

diastrophic movement and the landmass appeared above the sea level by the end of crefaceous period, and thus the plains were formed.

 

(2) Peneplains: Peneplain is an undulating surface of low relief,

interspersed with occasional residual hills, known as MONADNOCKS,and claimed to have been formed by the widening of flood plains and the wearing doen of interfluves by sub-aerial denudation. It is regarded as the end-product of the normal cycle of erosion. Although there are few large Peneplains at base level today, many uplifted peneplains, particularly in Scottish Highlands, Appalachians and Rocky Mountains may be seen.One of the most perfect uplifted peneplains is in East Central Africa.

 

(3) Flood Plains : Flood Plain is that part of river valley adjacent to the

channel, over which a river flows in times of floods. It is a zone of low

relief and gentle gradient and may incorporate or bow lakes, point bars,

abandoned channels, scrolls, all indicative of the fact that the river

channel has shifted its position continuously during the present regime of stream. The floodplain is composed of Alluvium, which generally buries

the rock floor of the valley to variable depths. The Indo-Gangetic plain and the plains of Mississipi, Amazon, Nile, Hwang-Ho, Yangtze Kiang,Ob, Yenesi, Lena, Volga rivers are good examples of flood plains.

 

(4) Delta Plains : As rivers draw near seas to disappear in them, their

flow goes dead slow. It necessities the waters to deposit all types of materials being carried by it. Such depositions are made in triangular shape which resembles to Greek word ‘Delta’. Thus formed plains are known to be best furtile plains of the world. Their examples are Sunderbans of Ganga and Brahmputra deltas of Nile and Mississippi etc.

 

(5) Glaciated Plains: In general, the great glaciated plains of Central

North America and Western Europe were plainsbefore they were Glaciated. However, the glaciers superimposed a new topography on the old. Drumlins, eskers, morains of different types, lakes, basins, Marshes and lacustrine plains dominate the present relief. Important changes have been made in the Pre-Glacter Drainage.

 

(6) Aeolian or Minor Plains:In this group may be included the wind swept plains of bolsons,playas, bajada sedi ments, lava and ash plains, lacustrine, lagoon and marsh plains and uplifted wave-cut plains-all of which are distinctive in their mode of origin and present characteristics. Sahara and Thar are examples of aeolian plains while plains formed by filling of lakes in

Kashmur, in Manitoba of Canada, lava plains of Idaho (U.S.A.) and plains

of Macca & Madina also fallin same category.

 

 

Importance of plains for mankind :

1. Plains are often referred to as the ‘cradles of civilizations’ and the

“food baskets’ of the world. Around 80% population lives in great plains of the world, i.e., Prartes (U.S.A), Steppes, Pustaz (Europe),Veld (S.Africa), Great Indo-Gangetic Plains of India, Downs

(Australia), Canterburry plains of NewZealand are famous for their

fertile soils.

 

2. Undulating and fertile land of plains is beneficial for conducting agricultural activities and irrigation. Crops are grown in plains in

abundance.

 

3. Developing means of transport like building roads, lying railways,preparing air strips etc. is possible and easy in plains.

 

4. Commercial facilities are more abundant to promote industry and

trade in plains.

 

EXERCISE

1. Answer the following questions in few words :

(a) Which is the common example of inland mountains in India?

(b) What tenure or period is known as Post Cambrian period ?

(c) What was the name of Super Continent prior to the drift ?

(d) What are the two parts of Earth’s top plate ?

(e) Which landform is known as ‘Heart of Asia’ ?

(f) Which is the best example of dommed plateau in the world ?

(g) Which river in Africa forms “flood plains’ ?

(h) What name is given to river (alluvial) plains in Austraia.

(4) What are Praries, Pampas and Canterbury ?

G) From which point the height is measured on the Earth ?

 

2. Answer the following in a sentnence or two :

(a) In which categories (portions) relief may be divied ?

(b) Classify mountains on the basis of size.

(c) Define Fold Mountains.

(d) When and in which book did Alferd Wagner present his continental theory ?

(e) Which region was known as Luresia earlier ?

(f) What is a border plateau ?

(g) Name the rivers of China and Russia known for, their alluvial

plains.

 

3. Answer the following in 60 to 80 words :

(a) Define Block Mountains.

(b) If you are living in a region having facilities of agriculture,irrigation and transport, which geograhical (relief) region it may be ? Name such regions of the world.

(c) Which geographical region has abundance of mineal resources, explain citing examples from world over.

(d) Explain theory of Plate Tectonic.

(e) Which geographical (relief) region supports water falls, rare and costly wood and thick forests ? Explain in short citing examples.

(f) What do you understand by mountain building or Orogeny ?

 

4. Answer the following in 150-250 words:

(a) What may be various bases of classification of mountains ?Give details of classification on basis of origin.

 

(b) Classify plateaus and write short note on each type.

 

(c) Compare the facilities and problems that people living in plains may enjoy and face in contrast to those living in

mountainous region.

 

(d) Explain various types of plains on the basis of origin.

 

(e) How the people living in Chhota Nagpur Plateau region may experience difference to the people living in Kerala and Himachal Praesh,respectively. Explain.