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Discuss the theories Explaining the Earth's Movements

Discuss the theories Explaining the Earth's Movements.

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Theories Explaining the Earths Movements

A theory is reasoned ideas intended to explain facts or ideas.
There are 2 theories which explain the earth’s movements namely the Continental Drift Theory and the Plate tectonics theory.

i)Theory of Continental Drift

Its proponent was A. Wegener.
It explains the origin of 6 continents.

It states:

- The earth was a single sialic land mass called Pangaea surrounded by a huge ocean called Panthalasa whose floor was a mass of sima.
- Pangaea broke into two parts called Laurasia (N. Hemisphere) which lay around equator and Gondwanaland (S. Hemisphere) which lay around south pole which were separated by a narrow ocean called Tethys (the present Mediterranean Sea).
- Laurasia broke into Laurentian Shield and Fennoscandia (Europe, Asia and N. America) and moved northwards to their present positions.
- Gondwanaland broke into Africa, Australia, S. America and Antarctica and India subcontinent.
- Africa and India drifted northwards.

Evidences Supporting the Theory

1. Fitting of western coast of Africa and S. America into a jigsaw.
2. Discovery of coal 40?N and 55?N which was formed by burying of tropical vegetation.
3. Considerable displacement of rocks along some faults e.g. along the Great Glen Fault of Scotland.
4. Cape and Buenos Aires folds resemble one another by having east west trend.
5. Red sea shores show evidence of having undergone lateral displacement an indication that it was formed by movement of the earth’s crust.
6. Evidence of ancient Glaciation to the south of equator in Africa in Madagascar and India where there is presence of ancient glacial deposits suggesting these areas were once around South Pole.

ii)Plate Tectonics Theory

It states that:
- The earth’s crust is made of blocks called plates
Large Ones
1. Eurasian plate
2. Australian plate
3. Africa plate
4. Antarctic plate
5. N. American plate
6. S. American plate
7. Pacific plate
Smaller Ones
1. Indian
2. Arabian
3. Caribbean
4. Cocos
5. Somali plates
6. Juan de Fuca
7. Nazca
8. Philippine
9. Scotia

marto answered the question on March 22, 2019 at 11:12

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Discuss the theories Explaining the Earth's Movements

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