SEA FLOOR SPREADING THEORY - ADVANCED PHYSICAL GEOGRAPHY

SEA FLOOR SPREADING THEORY – ADVANCED PHYSICAL GEOGRAPHY

This theory was provided by Proffer Harry Hammond Hess or Harry Hess of Princeton University in 1960’s which support the idea of continental drift theory.

The theory state that, “in all ocean there are presence of submarine mountain ranges with rift system, the way in which the molten materials from asthenosphere up welling. This mountain ranges are called Mid Oceanic Ridges, they are places of generation of new oceanic crust. They are zones in which molten materials are gusted and cool to solidify forming new rocks push away present rocks in divergence fashion. The molten materials are forced up to penetrate the crust from asthenosphere where the magma circulate called convectional currents.”

Beneath the mid oceanic ridges in the asthenosphere magma diverge and drive the crust away from each other.

EVIDENCES OF SEA FLOOR SPREADING

1. Presence of mid oceanic ridges.

2. Presence of fractures and rifts at the mid oceanic ridges

3. Differences in ages of rocks along the seafloor.

4. Magnetic evidence.

5. Presence of oceanic trenches.

IMPACTS/STRENTH OF SEA FLOOR SPREADING THEORY

1. It helps to understand the causes and formation of new lithosphere when magma cool and solidify at mid oceanic ridges.

2. Formation of transform offset faults with rift systems in the mid oceanic ridges.

3. Formation of submarine mountains called Mid Oceanic Ridges eg. Mid Atlantic ridges in the Atlantic Ocean.

4. The fact that, rocks near to Mid Oceanic Ridges are young in age then towards the continent. This is the due to divergent movement of sea floor centre of mid oceanic ridges.

5. Formation of shallow depth earth quake.

6. Formation of volcanoes and volcanic Island eg. Ice land in the North Atlantic Ocean.

7. On the land masses spreading movement gives rise to the formation of rift valley.

8. Formation of deep trenches as well as the reasons for sea floor spreading.