Computer model solves mystery of ancient supercontinent's demise

Washington, April 24 : A new computer model has solved the mystery behind the breaking up of Gondwana, the ancient supercontinent.

Dr Graeme Eagles from the Earth Sciences Department at Royal Holloway, University of London, and Dr Matthais Konig from the Alfred Wegener Institute developed the model for Polar and Marine Research in Bremerhaven, Germany

Gondwana was a 'supercontinent' that existed between 500 and 180 million years ago.

It comprised of most of the landmasses in today's Southern Hemisphere, including Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent of the Northern Hemisphere.

Between around 250 and 180 million years ago, it formed part of the single supercontinent 'Pangea'.

For the past four decades, geologists have debated how Gondwana eventually broke up, developing a multitude of scenarios which can be loosely grouped into two schools of thought.

While one theory claims that the continent separated into many small plates, a second theory claims it broke into just a few large pieces.

Now, a computer model developed by Dr Eagles and Dr Konig shows that the supercontinent cracked into two pieces, too heavy to hold itself together.

Evidence suggests that Gondwana began to break up at around 183 million years ago.

Analysing magnetic and gravity anomaly data from some of Gondwana's first cracking points - fracture zones in the Mozambique Basin and the Riiser-Larsen Sea off, Dr Eagles and Dr Konig reconstructed the paths that each part of Gondwana took as it broke apart.

The computer model reveals that the supercontinent divided into just two large, eastern and western plates. Approximately 30 million years later, these two plates started to split to form the familiar continents of today's Southern Hemisphere.

"You could say that the process is ongoing as Africa is currently splitting in two along the East African Rift," said Dr Eagles.

According to Dr Eagles and Dr Konig's study, because supercontinents like Gondwana are gravitationally unstable to begin with, and have very thick crusts in comparison to oceans, they eventually start to collapse under their own weight.

"These findings are a starting point from which more accurate and careful research can be made on the supercontinent," said Dr Eagles.

The new model also challenges the positions of India and Sri Lanka in Gondwana which have been widely used for the past 40 years, assigning them very different positions in the supercontinent, added Dr Eagles.

ANI