WASHINGTON: A new research has shed light on how India rapidly moved toward Eurasia 80 million years ago.
The study conducted by Massachusetts Institute of Technology (MIT) showed that more than 140 million years ago, India was part of an immense supercontinent called Gondwana, which covered much of the Southern Hemisphere and around 120 million years ago, what is now India broke off and started slowly migrating north, at about 5 centimeters per year.
Then, about 80 million years ago, the continent suddenly sped up, racing north at about 15 centimeters per year about twice as fast as the fastest modern tectonic drift. The continent collided with Eurasia about 50 million years ago, giving rise to the Himalayas.
For years, scientists have struggled to explain how India could have drifted northward so quickly. Now geologists at MIT have offered up an answer i.e.
India was pulled northward by the combination of two subduction zones regions in the Earth’s mantle where the edge of one tectonic plate sinks under another plate. As one plate sinks, it pulls along any connected landmasses. The geologists reasoned that two such sinking plates would provide twice the pulling power, doubling India’s drift velocity.
The team found relics of what may have been two subduction zones by sampling and dating rocks from the Himalayan region. They then developed a model for a double subduction system, and determined that India’s ancient drift velocity could have depended on two factors within the system: the width of the subducting plates, and the distance between them. If the plates are relatively narrow and far apart, they would likely cause India to drift at a faster rate.
Based on the geologic record, India’s migration appears to have started about 120 million years ago, when Gondwana began to break apart. India was sent adrift across what was then the Tethys Ocean, an immense body of water that separated Gondwana from Eurasia.
India drifted along at an unremarkable 40 millimeters per year until about 80 million years ago, when it suddenly sped up to 150 millimeters per year. India kept up this velocity for another 30 million years before hitting the brakes just when the continent collided with Eurasia.