An international team of scientists has discovered the first oceanic microplate in the Indian Ocean which revealed the collision between India and Eurasia occurred 47 million years ago.
Although there are at least seven microplates known in the Pacific Ocean, this is the first ancient Indian Ocean microplate to be discovered, says a paper published in the journal "Earth and Planetary Science Letters".
"The age of the largest continental collision on Earth has long been controversial. Knowing this age is particularly important for understanding the link between the growth of mountain belts and major climate change," said lead author Dr Kara Matthews from University of Sydney's School of Geosciences.
The new research shows 50 million years ago India was travelling northwards at the speed of some 15 cm a year — close to the plate tectonic speed limit. Soon after it slammed into Eurasia, crustal stresses along the mid-ocean ridge between India and Antarctica intensified to a breaking point. The crustal stresses caused by the initial collision cracked the Antarctic Plate far away from the collision zone, and broke off a fragment the size of Australia's Tasmania, in a remote patch of the central Indian Ocean.
"Dating this collision requires looking at a complex set of data, but we have added a new observation that has not been previously used to unravel the birth of this collision," explained Professor Dietmar Muller from the University of Sydney.
The authors, including Professor David Sandwell from Scripps Institution of Oceanography in the US, have named the ancient Indian microplate the Mammerickx Microplate after Dr Jacqueline Mammerickx, a pioneer in seafloor mapping.
According to Professor Sandwell, humans had explored and mapped remote lands extensively, but not for our ocean basins. "We have more detailed maps of Pluto than we do of most of our own planet because about 71% of the Earth's surface is covered with water," added Sandwell. The advances in comparatively low-cost satellite technology are the key to charting the deep, relatively unknown abyssal plains, at the bottom of the ocean, he pointed out.
Presently, the ongoing tectonic collision between Europe and Asia produces geological stresses that build up along the Himalayas and leads to numerous earthquakes every year.
