Competitive Exams: Continental Drift

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Continental Drift Theory

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This theory was propounded by Wegner who was trying to explain the past climatic changes in different regions. His theory depended upon the evidences like the juxtafixation of the opposite coast of Atlantic, presence of coalfields in temperate regions when they could only be formed in the tropical regions, evidences left by the glacial flow of the past, evidences of fossil fuels and similarity in the lithology of the rock structure on the opposite coast of the Atlantic. According to Wegner, the continents after breaking away from the Pangea(the unified landmass) moved along two directions - (l)equatorward movement (2)westward movement. The equatorward movement of continental blocks was caused by gravitational differential force and force of buoyancy. The westward movement of the continents was caused by the tidal force of the sun and the moon.

According to Wegner the Pangea, that is, the complete landmass as it was before any disruption, began to separate into Gondwanaland and Angaraland in the Carboniferous period. The intervening space between these two giant continental blocks was filled up with water and the resultant water body was called Tethys Sea, Gondwanaland was disrupted during Cretaceous period and Indian Peninsula, Madagascar, Australia and Antarctica broke away from the Gondwana-landand drifted apart under the impact of tidal force of the sun and the moon. Similarly N. America broke away from Angaraland and drifted westward due to tidal force. Similarly, South America broke away from Africa and moved westward under the impact of the tidal force.

Wegner was later criticized for his illogical consideration of the nature of forces behind the continental drift. Later on the findings associated with sea-floor spreading and paleomagnetism clearified the real forces behind the movement of continents.