A group of scientist in Australia who have been working and gathering data for the past twenty years claim that New Zealand sits atop a previously unknown continent which is 94% underwater.
Eight GNS Science geologists headed by Nick Mortimer along with colleagues from Victoria University, the Geological Survey of New Caledonia, and the University of Sydney summarize the evidence that 4.9 million square kilometers of the South West Pacific Ocean is underlain by a submerged continent.
The lead author Dr. Nick Mortimer in a press release said that Zealandia was former part of Gondwana. It measured five million square kilometers. It took them a long time to gather data as most of it was hidden under water. However it was bounded by well-defined geologic and geographic limits, Zealandia is, by their definition, is large enough to be termed a continent.
The paper has been published in the journal of the Geological Society of America Geological Society of America’s Journal, GSA Today, New Zealand is not just a few small islands at the bottom of the world. It is actually part of a fairly large continent 94% of which is under the sea.
Though Mortimer and his colleagues have drawn a similar conclusion before, they said that this paper will be a genuine surprise to many European, Asian, American, African and Australian geologists.
The main difference between Zealandia and other continents is that it has much wider and deeper continental shelves than the usual case. The highest point of Zealandia is Aoraki- Mount cook at 3724m.
“Currently used conventions and definitions of continental crust, continents, and microcontinents require no modification to accommodate Zealandia. Zealandia is six times bigger than Madagascar and about the same area as greater India” said Mortimer in a press release.
The research shows that Zealandia is a young, thin continent with crust thickness of between 10km and 30km, increasing to 40km under parts of the South Island. Zealandia provides a fresh context in which to investigate processes of continental rifting, thinning, and breakup
“The importance of Zealandia is not so much that there is now a case for a formerly little-known continent, but that, by virtue of its being thinned and submerged, but not shredded into microcontinents, it is a new and useful continental end member,” the paper says.
“To date, Zealandia is little-mentioned and/or entirely overlooked in comparative studies of continental rifting and of continent-ocean boundaries. By including Zealandia in investigations, we can discover more about the rheology, cohesion, and extensional deformation of continental crust and lithosphere,” it adds.
The paper thus concludes that the scientific value of classifying Zealandia as a continent is much more than just an extra name on a list. That a continent can be so submerged yet unfragmented makes it a useful and thought-provoking geodynamic end member in exploring the cohesion and breakup of continental crust