21 Febrero 2017 13:54
Until now, it was considered common knowledge that Earth was formed of six continents: Africa, Australia, Antarctica, North America, South America and Eurasia. To those six, it looks like we must now add a seventh: Zealandia, which, being about the size of India, would be the smallest of them all.
At about the size of India, Zealandia would be the world's smallest continent
The name 'Zealandia' was first proposed in 1995 by geophysicist Bruce Luyendyk as a collective name for the New Zealand and New Caledonia islands. It was believed to be a chain of islands left behind by a piece of land that broke away from Australia 80 million years ago. But it looks like the truth was hidden beneath the ocean.
According to a new report published in GSA Today, Zealandia should be classed as a continent. The idea has been floating around the scientific community since the middle of the last decade, but there hadn't been sufficient geological evidence to support the theory. But now, using rock samples and new elevation and gravity maps based on satellite imaging, an international team of geologists has concluded that Zealandia is not made up of a chain of islands – it is a single landmass.
'If the elevation of Earth's solid surface had first been mapped in the same way as those of Mars and Venus (which lack... opaque liquid oceans) we contend that Zealandia would, much earlier, have been investigated and identified as one of Earth's continents,' they wrote in the report.
Only 5% of this seventh continent is visible, the rest is submerged below water. In total, the continent is 4.9 million square kilometres.
Zealandia is separated from Australia by 25 kilometres of ocean. Rock samples confirm that it is the same continental crust that split from Gondwana.
Zealandia is divided into northern and southern segment by two tectonic plates: the Australian plate and the Pacific plate. This split makes the region look more like a group of continental fragments than a unified slab. The interaction of the plates also means that the area is volcanically very active.
If Zealandia is officially recognised as a continent, this could have economic repercussions. The area is rich in mineral deposits and fuels, most of which are extracted by New Zealand. If the boundaries of the country broaden to reflect the geological reality of Zealandia as a unified landmass, the country could find itself sitting on top of billions of dollars of new resources to exploit.
[Via Science Alert]