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Continental drift theory by Alfred Wegener

Continental drift theory of Alfred Wegener
Continental drift theory, basically means the way that resulted the present location of the continents and oceans. Various theories regarding the drift of the continents and oceans were forwarded by numerous geographers, among which the Continental drift theory by Alfred Wegener, was considered the most valid and significant one. Wegener had, not only simply put forwarded his theory of continental drift, but at the same time he had also given certain evidences in support of his theory. Although many criticized his theory in certain ways, but it cannot be denied that Wegener's theory along with the evidences or favoured arguments were false. It is considered to be significant even today. It is mainly through the Continental drift theory by Alfred Wegener, that many got brief idea about the way and reasons of the drift of the present continents and oceans.

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Continental drift theory

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Continental drift theory by Alfred Wegener 

The hypothesis of continental drift theory was put forwarded by the German scholar Alfred Wegener, in the year 1912. He had put forwarded this hypothesis in order to explain the distribution of the present day oceans and continents. Moreover, he was interested in the distribution of past climates. The second edition of  'Die  Enstehung Der Kontinente Und Ozeane' was the book from which Alfred Wegener has derived his views. Extensive hot and Arctic climates were found where there was least expectations, according to extensive studies. This could have only be possible by the laws of sun's control or by drift of continents.  Wegener emphasised only on the carboniferous period, for the development of the present globe's features. According to him during this period there was a landmass called Pangaea, which was surrounded by a huge water body called Panthalasa. The Tethys sea was at the middle of this landmass. Towards the north was the landmass Laurasia, which further consisted of North America, Europe and Asia. And towards the south was the landmass Gondwana, which further consisted of South America, Africa, Peninsular India and Antarctica. The Pangaea broke apart at the later stages and began to drift towards the equator and towards the west.

Direction of the drift :

1. Towards the equator 
The drift of the continents towards the equator occurred due to the force of gravity and force of buoyancy. This specific movement resulted in the formation of the Alps and the Himalayas.

2. Towards the west
The drift of the continents towards the west occurred due the tidal forces, that is the forces of sun and moon. This specific movement resulted in the formation of the Andies and the North American Cordillera.
Due to the movement of the continents in these two specific directions, the Americas were formed and between America and Africa the formation of the Atlantic ocean resulted. Further, Australia drifted towards north and to some extent towards south to get separated from Antarctica and Gondwanaland respectively. The formation of the Indian ocean, further resulted due to this.

Arguments in favour of the hypothesis of continental drift :

Alfred Wegener had forwarded certain arguments in order to prove his hypothesis.The basic and significant arguments were 

1. Jig-saw-fit - According to Wegener, there are certain regions which exactly will get fit if joined together. He had given the evidence of jig-saw-fit of the coastline of North America and South America with Western Europe and Africa ; Sierra-de-tandil of South America with Cape mountain of Africa ; Appalachian mountain of America and Caledonian mountain of  Britain ; Gulf of Guinea with bulge of Brazil ; Greenland, Baffin land and Elsemere island ; India, Africa and Madagascar.

2. Shift of Greenland - The gradual shift of Greenland towards North America has been noticed. It is moving at a rate of 20 cm per year. Vancouver has also been shifted towards Ottawa at a rate of 19 feet during a period of nine years.

3. Movement of lemmings - The lemmings of the northern part of Scandinavia has a tendency to move towards west when their population becomes high. They are founded on the sea due to the absence of land beyond the Norwegian coast, further proving the unity of the the ancient landmasses.

4. Evidence of fossils - The fossils of the similar flora and fauna are found on either side of the Atlantic ocean. Moreover, Glossopteris vegetation is found South America, India, Australia, Antarctica etc, further proving again the unity of the ancient landmasses.

Arguments in against the hypothesis of continental drift :
Although Alfred Wegener had given certain evidences to prove his hypothesis, which was one way or the other correct, but at the same time there were numerous people who were against his theory. They believed that his theory was based on certain speculations.

1. The forces of gravity and buoyancy and the tidal forces which was responsible for the equator ward and west ward drift of the continents respectively was not so adequate and sufficient. These forces had to be 10,000 million times more powerful for the resultant affect and if such happened it would have stopped the earth's rotation within a year.

2. The Rockies and the Andies mountain system could not have been formed in the manner as suggested by Wegener. This is because the sima could not offer much resistance to the sial, for the west ward movement of the continents and to form folded mountains.

3. The jig-saw-fit of the regions of the opposing areas of the Atlantic ocean was not adequate. It is vastly unnatural that there would be an exact fit of the continents after the drift. The drift of continents and that of the coasts had no link in between. 

4. The ice sheets did not spread in the direction mentioned by Wegener, according to Du Toit. He further suggested that similar climatic conditions can also result in the formation of ice sheets in different continents.

The earth's history comprises of various periods and there exists a vast difference between early and present day earth. The hypothesis of Continental drift theory by Alfred Wegener, clarifies certain confusions regarding the formation and location of the present day continents and oceans of the earth. Wegener's theory of continental drift, enables us to know about the present day earth in the most precised way.

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