The Origin of the Himalayas: The Himalayan range is a young fold mountain. It was formed by the formation of folds in the layers of the sedimentary rocks.
About 100 million years ago, there was a shallow sea named Tethys, where the present Himalayan range is situated.
On the either side of the Tethys ocean, there were two ancient landmasses. One was on the northern side named Angaraland and the other was on the southern side named Gondwanaland. Rivers from these lands brought down sediments and deposited them into the Sea. Layer upon layer sediments accumulated and in course of time they solidified into sedimentary rock.
Then a series of earthquakes occurred and the two ancient landmasses, i.e. the Angaraland on the north and the Gondwanaland on the south began to move each other. They extend a tremendous horizontal pressure from both the sides on the underlying sedimentary rock beds at the bottom of the Tethys Sea. This resulted in the formation of the folds. Thus a series of folds rose up from the Tethys to form a huge mountain; the Himalayas, and the Shallow Sea ultimately went out (obliterated). The geologists believe that the rise of the Himalayas is still going on.
The plate Tectonic Theory suggests that the movement of the oceanic plates induces the continental plates to move each other resulting in the compression force on the underlying rock beds to form folds and the fold mountain.