How did Indian peninsula or Gondwana island drifted northward to join the Eurasia 80 million years ago? The decades-old mystery re-surfaced again with geologists at the Massachusetts Institute of Technology (MIT) coining their own version.
The study says that India was pulled by two subduction zones in the Earth’s mantle when the edge of one tectonic plate sinks under another plate. And they have showcased evidence by sampling and dating rocks from the Himalayan region.
In support of their double subduction system behind India’s ancient drift, they said the width and distance could have played a vital role in increasing the velocity with which the the huge land mass must have moved to join the Eurasian plate.
“In the Earth science, it is hard to be completely sure of anything. But there are so many pieces of evidence that all fit together here that we are pretty convinced,” said Leigh Royden of MIT.
In fact, India has been a mystery for ages as it was originally part of the Gondwana land or supercontinent and 140 years ago began its drift towards the Eurasian continent and finally evolved into what is now part of Asia. The resultant Himalayas, which remained the highest mountain ranges in the world, were cited as the prime rationale behind the theory.
“When you look at simulations of Gondwana breaking up, the plates kind of start to move, and then India comes slowly off of Antarctica, and suddenly it just zooms across – it is very dramatic,” Royden said, hinting that about 120 million years ago, India might have broken off to set its sail migrating northward at about five centimetres per year for about 40 million years, before increasing the speed to 15 inches per year, making it one of the fastest tectonic drift, he said.
Finally, the Indian continent collided with Eurasia about 50 million years ago, giving rise to the Himalayas, concluded the MIT study based on their new model of “Double Subduction” involving a northern and a southern plate.
The researchers also calculated how the plates would move or sank into the Earth’s mantle based on the dimensions of the plates. According to their calculations, India would have sped up from 50 to 150 millimetres per year. “This is the first evidence that double subduction acted as the continent’s driving force,” the authors noted.
The study has been published in the journal Nature Geoscience.
Recently, some fossils of the horse, the rhino and the tapir found in India led researchers to solve age-old riddles concerning the common ancestor for the these animals and more than that the fossils reiterated the contention that India, ancient Gondwana island, was once separated from the mainland.
Scientists from Johns Hopkins University, with paleontological debris in Wyoming moved to India in 2001 and found in an open-pit coal mine near Mumbai a mother-of-all 200 Cambatherium thewissi fossils.
These ancient animals, called Perissodactyla, lived 56 million years ago and the “odd-toed” ungulate belonged to this group with odd-numbered toes on their rear feet. Though the fossil record was rather thin, it helped researchers crack the so-called “missing-link” in evolution of these animals.
The Cambaytherium was considered the youngest Perissodactylia ever discovered and believed to be the missing link between older and younger animals and the new fossils connect both biological and geographical evolution.
In paleogeography, Gondwana or Gondwanaland, is the name given to the continent, which was, alongwith the Laurasia, was part of the Pangaea supercontinent that existed from approximately 510 to 180 million years ago and mysteriously, it was referred in Vedic scriptures as “Jambudweep”.
Gondwana formed prior to Pangaea, broke up after the break up of Pangaea. Gondwana is believed to have sutured between about 570 and 510 million years ago, thus joining East Gondwana to West Gondwana. It separated from Laurasia about 200-180 million years ago during the mid-Mesozoic era.
Gondwana included today’s Southern Hemisphere, including Antarctica, South America, Africa, Madagascar, and the Australian continent, besides the Arabian Peninsula and the Indian Subcontinent.
The name Gondwana was given by Austrian scientist Eduard Suess, after the Gondwana region of central northern India from Sanskrit Gondavana “forest of the Gonds”. Gonds are a prominent tribal population in India.