Write a note on sea-floor spreading.
Answers
SEA FLOOR SPREADING :-
Sea floor spreading is a geologic process where there is a gradual addition of new oceanic crust in the ocean floor through a volcanic activity while moving the older rocks away from the mid oceanic ridges.
The mid oceanic ridge is the place where the sea floor spreading occurs,in which tectonic plates (large slabs of earth's lithosphere)split apart from each other.
Sea floor spreading was proposed by an American geophysicist, HarryH.Hess in 1960. By the use of sonar , Hess was able to map the ocean floor and discovered the Mid Atlantic ridge(mid-ocean ridge).
He also found out that temperature near the mid Atlantic ridge was warmer than the surface away from it.
He believed that high temperature was due to the magma leaked ou from the ridge. The continental Drift theory of Alfred wagener in 1912 is supported by this hypothesis on the shift position of the Earth's surface
In the picture, you can see that the magma from the oceanic volcanoes comes out and helps in the sea floor spreading. The oceanic crust pushes the continents when the magma hits the oceanic crust.
