GS I (Geography) (Duplex)
What is sea floor spreading? Explain with the evidences in support of it. Describe link between it and the Plate Tectonic Theory.
Best answer
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Scientists have tried to come up with explanations for the earthquakes and land formations on earth. Continental drift theory provided tidal and pole-fleeing forces as the reason which was not accepted by many scholars. Then, Sea floor spreading theory was proposed claiming that the crust below the oceans is expanding. The magma from inside the earth is being released deep below oceans on the oceanic crust which is causing the lava to be pushed on either side of mid-ocean ridges and thus spreading of the floor.
Evidences:
– Volcanic eruptions under the oceans bringing out huge amount of lava on the surface
– Rocks on either side of Mid-Oceanic ridges are very similar in their age and composition and magnetic properties
– The oceanic crust rocks are much younger than the continental crust
After the sea floor spreading theory, scientists came up with Tectonic plate theory which mixed both earlier theories in a way. Sea floor spreading proposed the magma as the cause of new crust and subduction of crust at the ocean-continent boundaries. This was further expanded by scholars to propose plates and their movement due to this magma. It is these tectonic plates and not the continents that have been moving since the inception of earth.
