PHYSICAL GEOGRAPHY GS1( CONTINENTAL DRIFT THEORY)

iasgurujee.blogspot.com                             Continental Drift theory

:-Rifting and drifting of the continent ,which has gives rise to  present the arrangement of the continents as well as change in the climate region of the world.

Basic assumption of the theory::-

:- Rial floating on Seema the force responsible for the drifting of the Earth is 

1.Tidal force 

2.  The gravitational force

Theory:=

Before the carboniferous Period there was a supercontinent PANGIYA, which was surrounded by the super Ocean known as PANTHALASSA in the curboniferous period broken into two parts Northern part and southern part.

Northern part was known as Laurasia  and southern part who was known as Gondwanaland, after carboniferous period they broken part was started drifting North and South wards .This phase is known as opening of the tethys sea .

The Laurasia land further broken  into North America and Eurasia and gondwanaland broken into South America ,Africa, Madagascar ,Peninsular India ,Australia and Antarctica.

 The drifting of the both the America westwords and resulted into the opening of S shaped Atlantic Ocean.The north words  drifting of the India and Africa reduces the sizes Tethys seapresent day Mediterranean sea and  also open up Indian Ocean.

 ACCORDING to the WagonR while drifting the basis of continent due to friction and resistance were folded to form the mountain such as Rocky and ANDES ETC.

According to the WagonR Iceland arcs and festoons were formed due to differential rate of movement some part was left Behind giving rise to Iceland arcs .

 THE ORIGINAL PANTHALASSA WAS reduces in size to form present the Pacific Ocean.

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CRITICISM OF WAGNER,S theory 

1. It cannot explain the force responsible for the drift because tidal force cannot so  strong and their forces can not for the rifting and drifting of te continent.

2. WagonR could not explain the trigger mechanism for the breaking of the PANGIYA in carboniferous period. 

3. He could not explain the sequence of breaking and drifting of the continents.

4. There were a lot of error in the WagonR theory regarding the formation of mountains Iceland arcs and festoons.

Evidences

1. Jigsaw fit of the continents.

2. The Rock of the same age, type and formation of mountains across Atlantic.

3. The mountains of aplacian Ireland and Scandinavian country this is possible only e-iph continents joined together.

4. There are huge gold deposit in western Africa especially gana (Gold Coast)  but the gold bearing rocks are found across Atlantic in South America.

5. BEHAVIOR OF ANIMALS:- animals in Africa Europe even today tendency to run best words this is best explained by lemmins Scandinavian.  lemmins migrated best words when ever population increase but they fall into sea on the Norway coast.

6. Distribution of fossils :-There are numerous type of fossil which had found that many forces of flora and fauna are found in Brazil, Africa ,Peninsular India and Australia. Example GLOSSOPETRIS FLORA.

7. EVIDENCES OF GLACIATION IN BRAZIL, AFRICA, AUSTRALIA, AND PENINSULAR INDIA ETC.

    CONCLUSION::- THOUGH WAGONR COULD NOT EXPLAIN THE FORCES RESPONSIBLE FOR THE DRIFTING BUT IT CENTRAL IDEA OF DRIFTING HELP IN DEVELOPMENT OF PLATE TECTONIC THEORY. 

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MAINS QUESTION PRACTICE

Q1. Write a short note on continental drift theory.

                 Or

examine the limitation evidence of continental drift theory .

               Or

critically analyse the continental drift theory.