Strange fact: India was once an island!
India is a country and a part of the Asian continent. But what if someone told you that it was once a continental island? Unimaginable, right? But it is true. Geologically speaking, the Indian subcontinent originated from Insular India, an isolated landmass that rifted from the supercontinent of Gondwana during the Cretaceous period and merged with the landmass of Eurasia nearly 55 million years ago, forming the Himalayas. Let us dive more into the evolution of India from an island to the country it is now. from the supercontinent of Gondwana during the Cretaceous period and merged with the landmass of Eurasia nearly 55 million years ago, forming the Himalayas. Let us dive more into the evolution of India from an island to the country it is now. during the Cretaceous period (a geological period about 145 to 66 million years ago) and merged with the landmass of Eurasia nearly 55 million years ago, forming the Himalayas. Let us dive more into the evolution of India from an island to the country it is now.
From Pangea to Gondwana & Laurasia
Millions of years ago, India as we know it, was not a part of Asia like it is today. The world was one big single landmass called Pangea. Eventually, this landmass broke and formed two super landmasses or supercontinents – Gondwana and Laurasia. Until roughly 140 million years ago, the Indian subcontinent was a part of Gondwana along with modern Africa, Australia, Antarctica, and South America together covering much of the Southern Hemisphere while Laurasia comprised Eurasia, North America and Greenland.
Birth of Insular India or Isolated India
Due to the internal forces of the Earth, Gondwana broke further around 120 million years ago. At that time, most of what is now India was an island continent, called insular India. It started a northward drift towards Eurasia (which also broke off from Laurasia) across what was then the Tethys Ocean, an immense body of water that separated Gondwana from Eurasia, at about 5 centimetres per year.
Formation of the present India
About 80 million years ago, this Insular India suddenly increased its speed, racing north at about 15 centimetres per year. Finally, the continent collided with Eurasia about 50 million years ago. But this also led to the birth of Himalayas - the world's youngest major mountain range - and, of course, the highest. Since both the continental landmasses had about the same rock density, one plate could not be subducted under the other. The pressure of the plates could only be relieved by rising skyward and forming the jagged Himalayan peaks. At the same time, the collision slowed India’s northward advance considerably.
How do we know it is true?
Well, there is evidence to support this in the fossilised sea shells found high in the Himalayan mountains. Also, India’s status as an island has allowed its local biota to follow the typical patterns seen in islands and diversify in unique ways, according to geologists. This is not all. The tectonic plate on which the Indian subcontinent rests still continues to press slowly towards north by around 5 cm a year, causing Mount Everest to grow by about 0.4 cm a year although other parts of the Himalayas are rising at around 1 cm per year. Now you know why the height of Mount Everest increases slightly every year!