The earlier idea that the floor of the ocean basins were largely vast, flat to undulating plains with relatively little relief, dull and featureless was proved to be incorrect by the results obtained from the analysis of the outcomes of various geophysical techniques, echo-sounding, coring, bathyscaphe descents etc.
It was confirmed that the ocean basin are characterized by the following important features.
– Mid oceanic ridges, along which the formation of new oceanic crust takes place
– Abyssal plains, which are extremely flat and monotonous in relief occur at depths of 3500 to 6000 metres.
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– Isolated peaks rising from the ridge or plains which sometimes are emerged at the ocean surface to form islands. Besides, there are abyssal hills, sea-mounts, guyots etc.
– Deep, narrow oceanic trenches, where the old oceanic crust is destroyed.
The combination of the above discoveries which include the creation of new oceanic crust at the crest of the mid-oceanic ridges and its destruction at the deep oceanic trenches, with the movement of rigid sections-in between led to the idea of sea-floor spreading in the early 1960s.
Besides, the results of palaeomagnetism and of marine geology and geophysics set the scene for Hess’s formulation of the concept of sea-floor spreading. Professor Harry Hess of Princeton University was first to formulate the hypothesis of ‘sea-floor spreading’ in 1960.