The more discoveries we find about our planet the more we realise the enormity of things that are still likely to come to the surface. An indomitable task perhaps but one that will in time only add to our knowledge of the tremendous evolution of Planet Earth millions of years past.
People may well ask to define how many continents are there? A month ago, the answer would have been seven; today however you could venture to make a case for nine ; geologists are now arguing that we should add a new continent to those we already know – Zealandia, a submerged landmass half the size of Europe that only substantially breaks the ocean surface at New Zealand. In the Indian Ocean, a group of South African scientists say they have found the fragment of a lost continent they call ‘Mauritia’ after the island of Mauritius, deep beneath an ancient lava flow.
Given the fact that it is underwater, the world’s geographers could be forgiven for not spotting Zealandia until now. In a paper published in the Journal of the Geological Society of America, New Zealand researchers argue that it is no impediment to it being a continent. In order to be termed one, a landmass has to have four criteria ‘none of which technically require that it is actually ‘land’. It must be significantly elevated above the oceanic crust; have broad range igneous, sedimentary and metamorphic rocks; have a thick crust; and be a large and clearly defined mass.’ The scientists said that the slow accumulation of data about the region over the past decade led them to the conclusion that Zealandia met all the standards. It was not a sudden discovery but a gradual realization, they wrote.
If Zealandia is hard to spot, Mauritia is significantly more so. The fragment was identified deep underground by scientists who spotted it was significantly older than the surrounding crust. While Mauritius is about 9 million years old, this rock was as old as 3 billion.
‘Earth is made up of two parts – continents which are old and oceans which are young. On the continents you find rocks that are over 4 billion years old, but you find nothing like that in the oceans, as this is where new rocks are formed,’ Lewis Asawan, from Witwatersrand University, said in the online journal Nature Communications.
He and his colleagues suggested that the fragment came from a shattering of an ancient continent due to tectonic forces and bits of it were now scattered around the oceans. Professor Asawan said that the discovery meant that we should define more regions as continents, but that the definition itself was arbitrary.
What an interesting and beguiling earth we live in. However, it’s a pity that human life is short lived as to miss out on explorations such as these, to keep enhancing our knowledge on the enormity and incalculable mysteries of the universe.