History of Indian Ocean is much older than humans. The Indian Ocean is much more complex & alive than just a geographical being. Earlier it was to be believed that geography of the earth is certain. And relative positions of oceans & continents were fixed. But now we know that this is not correct. According to the book, “The Origin of Continents and Oceans” by Alfred Wegener, Continents had been part of a gigantic supercontinent and had later drifted apart like icebergs.
Early Movements of Plates & Creation of Indian Ocean
Around 270, million years ago, the continental land masses converged to form a gigantic supercontinent called Panega. At that time the Indian Ocean didn’t exist. Around 175 million years ago, the supercontinent began to split up due to a sequence of rifts. First, it had broken into two large land masses – Northern continent of Laurasia & southern continent of Gondwana. India & Madagascar broke away from Africa, and then, from Antarctica –Australia. About 90 million years ago, India broke away from Madagascar and started drifting north. Around 55 million years ago Indian plate collided with the Eurasian plate. It was this collision which created the Himalayas. Between 85 & 45 Million years ago Australia & Antarctica began to tear apart. After separation Australian plate shifted north & become fused with Indian Plate. All these geographical changes thus created the Indian Ocean.
Ever changing Coastal lines
Changes in the global temperature due to changes in weather had a huge effect on the Indian Ocean. Coastlines have been moving in and out because of periodic warming & cooling of the planet. Since the peak of last ice age around18-20000 years ago, the sea level has risen by 120 meters as the ice sheets have melted. The sea level began to stabilize about 7000 years ago and broadly remained unchanged between AD 0 and AD 1800, but it has begun to gradually rise since the nineteenth century.
Human Evolution along the Indian Ocean
A small group of Modern humans made it out of Africa about 65000 years ago and around 45000 years ago they reached Australia, on the other side of the Indian Ocean. A part of the population remained in the Persian Gulf –north India continuum and one by one other group migrated out. Some 40,000 years ago, another group made its way across India to South East Asia. One group from the Persian Gulf –north moved out around 30-350000 years back and settled in southern India. Since the sea level was much lower & coastlines were much further out. Sri Lanka was then attached to India.
First Signs of Farming
There have been various sites across the Indian Ocean rim. Some even 6000 years older than Stone Age. One such site was found near south eastern turkey. Another site has been found in Indonesia which belongs to the same time period as that of Turkey. Another site has been found in the Gulf of Khambat by India’s National Institute of Ocean Technology. Much detail has not been found about the site because of its depth underwater. But, there are signs that the site is much older than even 7500 years ago.
It has been believed that agriculture had a single point of origin in the Middle East and then migrants carried the knowledge to other places. We now know that both crops & animals were domesticated at multiple locations around the world at same time.
(The article is based on the book “The ocean of churn” by Sanjeev Sanyal.)