A new research has tried to uncover how tectonic plates of earth were created. The study found that the tectonic plates took around one billion years to form. The outermost layer of earth, or lithosphere, was debilitated by movements in viscous layers below it.

Cooler parts of crust of earth were pulled downwards into the warmer upper mantle around four billion years ago. This led to damage caused in the surrounding crust and it did not stop until the plate boundaries were formed by the weak areas.

"Over a much longer period, the same process could have created many tectonic plates. We have got a physical mechanism to explain how it could have happened", said study author David Bercovici from Yale University.

A computer model was created by Bercovici and Yanick Ricard of University of Lyon in France to look into the formation of the plates. A low-pressure zone at the base of the crust was included in the model to determine the process of formation of earth's crust.

Most of the evidence of origin of earth's crust was removed by the subsequent movement of the plates, said Paul Tackley, a geophysicist at Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland.

The findings of the study have been published in Nature. There is no firm evidence to show that the formation of tectonic plates occurred earlier than one billion years ago, said to Robert Stern, a geologist at University of Texas in Dallas. However, the study has provided significant insight into the new mechanism behind plate formation, which is the first example of how the process of formation tectonic plates might have occurred.

It was suggested by previous studies that the secret behind the age of the plates lies in ancient rocks. And the oldest such specimens are zircons found in the Jack Hills of Australia and they formed four billion years ago.