In the previous article you learned about the Geosyncline theory of formation of Himalayas, now you’ll learn about the Plate Tectonic Theory of Origin of the Himalayas.
This theory was put forward in 1967 by W. J. Morgan of Princeton University and the Morgan’s theory is based upon the concept of “Sea-Floor Spreading” advocated by H.H. Hess.
The supercontinent Pangea was divided into several tectonic plates. Indian plate and Asian plates were two of them. There was a sea called Tethys sea between Indian and Asian plate.
70 or 65 million years ago, Indian plate came very close to the Asian plate and started subducting under the Asian plate.
As you know, continental plates are huge in size and shape and the force exerted by them is also extreme. When Indian plate collided with the Asian plate, this collision exerted huge amount of force and the Tethys sea between these plates was squeezed and folded into three parallel ranges of the Himalayas – The Greater Himalayas, the Lesser Himalayas, Shiwalik or Outer Himalayas.
It has been estimated by the geologists that this collision has caused a crustal shortening of about 500 km in the Himalayan region and this shortening is compensated by sea floor spreading along the Indian oceanic ridge in the Indian ocean region.
Even today, Indian plate is subducting and moving northward into the Asian plate that’s why Himalayas are still rising.