Supercontinent Split Under its Own Weight

Five hundred million years ago, the Earth had a single supercontinent, Gondwana, located in the southern hemisphere, but one hundred and eighty million years ago it suddenly split. Different pieces of Gondwana started moving apart from each other, thus creating the seven continents we know today. The mystery of why this split occurred has been dominating the field of geology for the last four decades or so, albeit now a new model argues that the massive continent gave in to its own weight, simply cracking in two.

Most of the theories related to this event attack the problem from one of the two angles: either Gondwana broke up in a large number of fragment or in just a few. Magnetic and gravity anomaly measurements from what scientists believe to be the first cracking points - currently located in the Mozambique Basin and Riiser-Larsen Sea - reveal that Gondwana broke in just two pieces before separating into the other large plates forming the continents today.

The computer simulations conducted by the University of London in collaboration with researchers from the Alfred Wegener Institute for Polar and Marine Research not only simplify all the previous models, but also remove the problematic plume of hot mantle which could have occurred before and during the split.

Graeme Eagles from University of London says that "It doesn't require us to re-invent plate tectonics at break-up times." The new model does not need a plume of hot mantle to occur in order to split Gondwana, instead the supercontinent could have broken due to its own massive weight. Continents have much thicker crusts than the oceans, thus larger mass pressing on the mantle. Somehow it must have became unstable and snapped in two.

Critics of the two plates theory argue that the model is inaccurate. For example, Maarten De Wit of University of Cape Town says that "In order to make the continents fit they have to place Sri Lanka and India in a position not supported by geological data."