London, March 23 : A new computer model of Gondwana - the southern hemisphere supercontinent that existed between 500 and 180 million years ago, has suggested that it simply cracked in two, collapsing under its own weight.
According to a report in New Scientist, Graeme Eagles from Royal Holloway, University of London and Matthias K¶nig from the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, developed the model.
For the last 40 years, geologists have debated how Gondwana split apart.
There are two competing theories - one that says the continent was smashed to smithereens and the other that says it broke into just a few large pieces.
Now, using data gathered together from magnetic and gravity anomaly from some of Gondwana's first cracking points - fracture zones in the Mozambique Basin and the Riiser-Larsen Sea off Antarctica, Eagles and K¶nig have suggested that the supercontinent was too heavy to hold itself together.
Plugging these data into a computer model, Eagles and K¶nig plotted the path that different parts of Gondwana took, as the supercontinent broke apart.
The model supports the idea of Gondwana splitting into just two large plates.
A simple split is compelling because it removes the need for a plume of hot mantle underneath Gondwana to start the splitting process - an unusual behaviour for the Earth's mantle.
"It doesn't require us to re-invent plate tectonics at break-up times," said Eagles.
Instead, Eagles and K¶nig suggest that large continents like Gondwana are inherently unstable because they have very thick crust compared to oceans, making them spread outwards under their own weight.
Eventually, the groaning mass splits into a few large plates.