Short note of sea floor spreading

Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.

• Seafloor spreading helps explain continental drift in the theory of plate tectonics.

• This theory was proposed by Hess in 1961. He argued that constant eruptions at the crest of oceanic ridges cause the rupture of the oceanic crust and the new lava wedges into it, pushing the oceanic crust on either side. Thus,the ocean floor spreads.

• The younger age of the oceanic crust as well as the fact that the spreading of one ocean does not cause the shrinking of the other, made Hess think about the consumption of the oceanic crust.

• He further maintained that the ocean floor that gets pushed due to volcanic eruptions at the crest, sinks down at the oceanic trenches and gets consumed.

SEA FLOOR SPREADING
1 .it was proposed by Hess in 1961
2. he believed that new lava pushes out the plates from the mid-oceanic ridge
3. palaeomagnetic studies of the ocean floor reveal that
A. along the mid-oceanic ridge there is an intense volcanic eruption
B. huge amount of lava comes out along the mid-Atlantic ridges
C. the equidistant rock formations have similar age and chemical compositions & magnetic properties
7. rocks closer to the mid-oceanic ridges are young and normal polarity
8. The age of rocks increases as the distance increases from the mid-oceanic ridge
9. Oceanic crust is much younger(200my) than continental crust (3200my)
10. The sediments of ocean floor is very thin