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continental drift theory summary

By : brainykey   August 31, 2013

cdtAlfred wegner was a meteorologist and geophysicist and he was concerned with the following puzzling questions

  1. Why should tropical fern have grown in London,Paris and Bonn.
  2. Why coal fields are found in the cold climatic regions of the tundra.
  3. Why glaciers have covered parts of brazil,peninsular india,Australia,aouth America and congo basin at the same time.

  Wegner thought that such variations in climate could have taken place because of either reasons.

  1.If the continents remained stationary at their place,climate zone might have shifted from one region to another.

 2.If the climatic zones remained stationary,the land masses might have displaced and drifted.

 It therefore seems more probable to the wegner that the continents would have shifted.as per Alfred wegner there was a super continent called pangea which was surrounded by panthalasa.as per Alfred wegner,Equatiorial differential force and tidal force of the moon acted on the pangea which was lying in the southern hemisphere.

The equatorial differential force got the pangea to shift towards the north and resulted in the mountains eg alps.altai,teinshan,zagros,hindukush and Himalayas. The peninsula of india and Africa got separated from Europe and Australia.

Due to tidal force the continents began to move westwards and rockies and andes were formed as a result of the westward movement.

The northward ( equatorial) movement happened during the Mesozoic period but westward movement took place in the tertiary period.

 

Evidences in the support of the continental drift

  1. Geographical similarity in the opposing coasts of the atlantic ocean.
  2. Paleontological evidence
  3. Evidence from the structure and rock type.
  4. Evidence from glaciation.
  5. Paleoclimatic evidence.
  6. Polar wandering.

 

 Criticism

  1. He put forward the contradictory assumptions.
  2. Equatorial differential and tidal forces are not that strong forces what can cause the movement of continents.
  3. He highlighted the dynamic nature of the continents but remained silent on the dynamism of oceanic crust
  4. He failed to explain the processes of mountain building and volcanism.
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