Continents may not have been created in the way we thought

From the 1950s until recently, we thought we had a clear idea of how continents form. Most people will have heard of plate tectonics: moving pieces on the surface of the planet that collide, pull away or slide past one another over millions of years to shape our world.

There are two types of crust that sit on top of these plates: oceanic crust (that beneath our oceans) and continental crust (that beneath our feet). These move across the surface of the Earth at rates of up to 10cm per year. Many are in a state of constant collision with one another.

Their formation is undergoing something of a re-think................

http://theconversation.com/continents-may-not-have-been-created-in-the-way-we-thought-33334

LOST CONTINENT FOUND BY RADIOMATRIC DATING

A lost continent which sank millions of years ago has been found at the bottom of the Indian Ocean.

Named Mauritia by scientists, it is believed to have existed intact up to 85million years ago.

Part of this small microcontinent is still above water, and is now part of the Seychelles, a group of islands between Madagascar and India.

The discovery was made after sand from the beaches of Mauritius was analysed and found to be hundreds of millions of years older than expected.

The grains contained zircon minerals up to 1.9billion years old that may have formed part of the ancient land of Rodinia.

They were dragged 10km (6.2 miles) up to the surface after a volcanic eruption 9million years ago.

Zircon is something you typically find in a continental crust – they are very old in age.’

India drifted from Madagascar causing the microcontinent to break up and disappear into the sea. However, some of the land has survived.

‘At the moment, the Seychelles is a piece of granite, or continental crust, sitting practically in the middle of the Indian Ocean,’ Prof Torsvik, told the journal Nature Geoscience.

‘But once upon a time it was sitting north of Madagascar.

‘What we are saying is maybe this was much bigger. There are many of these continental fragments spread around in the ocean.’