Development Of The Ocean Floor

The landscape of the ocean floor is much like what you see on land just way more dramatic and without all that life.

Development of the ocean floor.

Wherever continents are bordered by deep sea trench systems as in the pacific ocean the ocean floor is plunged downward underthrusting the continents and ultimately reentering and dissolving in earth s mantle from which it had originated. Most plate boundaries are under the ocean. Our picture of the ocean floor greatly sharpened after world war i 1914 18 when echo sounding devices primitive sonar systems began to measure ocean depth by recording the time it took for a sound signal commonly an electrically generated ping from the ship to bounce off the ocean floor and return. Basalt the once molten rock that makes up most new oceanic crust is a fairly magnetic substance and scientists began using magnetometers to measure the magnetism of the ocean floor in the 1950s.

The magnetism of mid ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. The outer rocky layer of the earth includes about a dozen large sections called tectonic plates that are arranged like a spherical jig saw puzzle floating on top of the earth s hot flowing mantle. The development of this instrument greatly enhanced our knowledge of the ocean floor. It is believed that continental rocks formed 3 billion years ago however the sediments samples from the ocean floor are found to be not exceeding 200 million years old.

Scientific research submersibles have explored the ocean s deepest trenches but most are designed to reach only the ocean floor. Scuba divers can explore only to about 40 meters while most submarines dive only to about 500 meters. The deep ocean is dark very cold and has tremendous pressure from the overlying water. It is a clear evidence that the formation of rocks in the sea floor is due to reabsorption of materials.

Until the development of sonar we knew very little about the ocean floor. See also continental drift. All this evidence both from the ocean floor and from the continental margins made it clear around 1965 that continental drift was feasible and the theory of plate tectonics which was defined in a series of papers between 1965 and 1967 was born with all its extraordinary explanatory and predictive power. The ocean floor had tracks from the continents.

What they discovered was that the magnetism of the ocean floor around mid ocean ridges was divided into matching stripes on either side of the ridge. You ll see underwater mountains called seamounts cliffs trenches and. Bathymetry the shape of the ocean floor is largely a result of a process called plate tectonics.