Geological History of India
India is mostly located on the Indian Plate, which is generally called the northern portion of the Indo-Australian Plate. Indian subcontinent, Australia, New Guinea, and Tasmania, New Zealand etc. have a common geological history by virtue of being an integral part of the Mesozoic Gondwana super-continent until 160 million years ago.
The earth is 4700 million years old and the earliest supercontinent Vaalbara started forming around 3600 million years ago. It took nearly 400 million years to get completed and was ready by 3100 million years ago. Then, around 2500 years ago, Vaalbara started breaking. The result of this breaking was that another supercontinent Kenorland formed around 2700-2500 million years ago. The breaking kept on and then Supercontinent Columbia formed around 1800-1500 million years ago. Around 750 million years ago, a new supercontinent was formed that was called Rodinia. In the late Paleozoic period (542 – 250 million years ago) super continent Pangaea was formed that existed during the Paleozoic and Mesozoic eras. Pangaea started beginning to break up approximately 200 million years ago, before the component continents were separated into their current configuration. It first broke into Northern Laurasia (Angaraland) and Southern Gondwanaland.
Later, the Laurasia and Gondwana drifted apart. Gondwana included Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent, which have now moved entirely into the Northern Hemisphere.
Thus, from geological history two main structural divisions of India are:
- Himalayan Mountain Chain, which is a part of Laurasia or Angaraland
- southern pan called Gondwanaland of which Peninsular India formed one of the blocks.
The intervening space between the two giant continental blocks was filled with water. It was a shallow sea called Tethy’s Sea. During the subsequent geological periods, the Indian Peninsular block began drifting northward leaving a huge gap filled with water which truly came to be called the Indian Ocean. As the peninsular block continued its drift northward, the Indian Ocean continued to advance and filled up the depressions on either side of the landmass when it compressed the Tethy’s Sea. Thus, the Arabian Sea and Bay of Bengal were formed. What was once the Tethy’s Sea has become the Mediterranean Sea. Other remnants are the Black, Caspian, and Aral Seas (via a former inland branch known as the Paratethys).
The similarity in the geological formation produced more or less similar type of mineral wealth in both India and Australia. Despite the variance in the biotic life between India and Australia, there are certain endemic plant and animal species, pointing to the super continent connection.
Please note that Strait of Lombok is part of the biogeographical boundary between the fauna of Indomalaya ecozone and the distinctly different fauna of Australasia. The boundary is known as the Wallace Line, for Alfred Russel Wallace, who first remarked upon the striking difference between animals of Indo-Malaysia from those of Australasia and how abrupt the boundary was between the two biomes.