What is Zealandia?
It’s a new geological continent and consists of a chain of islands which include New Zealand and New Caledonia. Zealandia spreads out over 4.9-million-square kilometres of continental crust and was once a part of Australia. It broke off from Antarctica about 100 million years ago, and then from Australia about 80 million years ago. It may have been completely submerged about 23 Ma ago and most of it, which is 93% remains submerged beneath the Pacific Ocean, according to the findings that have been published by The Geological Society of America. Sea-floor samples show that Zealandia consists of light continental crust and not the dark volcanic rocks that make up nearby underwater plateaus. A piece of seafloor called the Cato Trough still separates Zealandia and Australia by 25 kilometres.
