A new study has pieced together the fragmented continental puzzle that scientists believe once comprised Gondwana -- the supercontinent believed to have broken up into the Antarctic, Australian and Indian tectonic plates. And the authors of the study have created an animated video showing how the supercontinent might have broken up 165 million years ago, and how the fragments ended up in their present-day locations. The project was a joint initiative between researchers at the Royal Holloway University, the Australian National University and Geoscience Australia. They used computer modelling to chart the path the tectonic plates would have followed over millions of years, after their initial break up. The process involved matching the geological boundaries of each of the plates, to the surface of their corresponding plates, and thereby put the "jigsaw puzzle" back together. "These geological units formed before the continents broke apart, so we can use their position to put the jigsaw pieces back together again. Many other reconstructions do not use the geological boundaries to match the continental jigsaw pieces back together -- so they don't align properly," said Dr. Lloyd White, from the Department of Earth Sciences at Royal Holloway University, in a post accompanying the video. In an abstract for the study, White said that’s why many recent models for the breakup of Gondwana have gotten it wrong. White and his team used an old technique originally used to discover continental drift and plate tectonics, but which has fallen out of favour with modern scientists. "It is important that we know where the plates existed many millions of years ago, and how they broke apart, as the regions where plates break are often where we find major oil and gas deposits, such as those that are found along Australia's southern margin," White told eScienceNews.com. The study was published Friday in the journal Gondwana Research. [LEFT] Read more: http://www.ctvnews.ca/sci-tech/scie...ndwana-supercontinent-1.1355243#ixzz2YToZxnYs [/LEFT]
^ And then what, the plates keep moving under & over each other, come out the other side(s) and the process starts over again?
When the oceanic portions of lithospheric plates subduct, they are believed to be destroyed in the asthenospheric mantle. They don't survive the process. The oldest oceanic crust is believe to only date from around the Jurassic period -- about 200 Ma. New oceanic crust is generated at divergent plate boundaries such as mid-oceanic ridges. There are believed to have been a number of supercontinent cycles in Earth's history since the time that plate tectonics "switched on" about 3.1 Ga. http://en.wikipedia.org/wiki/Supercontinent