Produced by: Tarun Mishra Designed by: Manoj Kumar
Scientists studying Earth’s geological history have observed that some of the planet’s oldest continental crusts, particularly in America and China, are breaking apart, a process that could reshape the planet’s surface.
Earth’s crust has undergone cycles of expansion and contraction throughout its history. These movements have altered the positions and topography of the continents, contributing to the current state of the planet’s crust.
While certain regions of the continental crust, known as cratons, have remained stable for billions of years, others have experienced significant destruction due to processes like mantle convection and tectonic activity.
A new study published in Nature Geoscience points to a process called decratonisation as the key reason behind the deformation of cratons. This phenomenon leads to the gradual disintegration of stable continental crust.
Experts suggest that subduction—where a denser mantle layer is pushed beneath another—and mantle plumes, where sections of the mantle rise due to buoyancy, may be responsible for the disintegration of cratons. However, the exact mechanism remains unclear.
Research by Professor Shaofeng Liu of the China University of Geosciences has focused on the disintegration of the North China Craton and nearby areas of the western Pacific Ocean, a process ongoing for more than 200 million years.
The North American, South American, and Yangtze cratons are also experiencing decratonisation. All of these regions may have undergone early flat-slab subduction, with varying subsequent tectonic activities, according to Professor Liu.
The study highlights that ancient lithosphere can break apart due to specific forms of subduction near oceanic plates. This ongoing process reveals how continents have evolved throughout Earth’s history.