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‘Himalayas were born 47 million years ago’

PTI
Published : Nov 10, 2015, 11:59 pm IST
Updated : Nov 10, 2015, 11:59 pm IST

Himalayas were born about 47 million years ago when India and Eurasia initially smashed into each other, an international team of scientists, who discovered the first oceanic microplate in the Indian

Himalayas were born about 47 million years ago when India and Eurasia initially smashed into each other, an international team of scientists, who discovered the first oceanic microplate in the Indian Ocean, has found.

Although there are at least seven microplates known in the Pacific Ocean, this is the first ancient Indian Ocean microplate to be discovered, the researchers said.

Radar beam images from an orbiting satellite have helped put together pieces of this plate tectonic jigsaw and pinpointed the age for the collision, whose precise date has divided scientists for decades.

The team of Australian and US scientists believes the collision occurred 47 million years ago when India and Eurasia initially smashed into each other. Researchers led by the University of Sydney School of Geosciences discovered that crustal stresses caused by the initial collision cracked the Antarctic Plate far away from the collisional zone and broke off a fragment the size of Australia’s Tasmania in a remote patch of the central Indian Ocean.

The authors, comprising Professor Dietmar Muller and Kara Matthews from the University of Sydney and Professor David Sandwell from the Scripps Institution of Oceanography, have named the ancient Indian microplate the Mammerickx Microplate, after Jacqueline Mammerickx, a pioneer in seafloor mapping.

The Mammerickx Microplate rotation is unveiled by a rotating pattern of grooves and hills that turn the topography of the ocean floor into a jagged landscape. These so-called “abyssal hills” record a sudden increase in crustal stress, dating the birth of the Himalayan Mountain Range to 47 million years ago, researchers said.

The new research shows that 50 million years ago, India was travelling northwards at speeds of some 15 centimetres 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 breaking point.

A chunk of Antarctica’s crust broke off and started rotating like a ball bearing, creating the newly-discovered tectonic plate.

Location: Australia, Victoria, Melbourne