What is Zealandia?
Zealandia is a large region in the southwest Pacific Ocean underlain by continental crust. It includes New Zealand and New Caledonia, but also extensive regions underwater, such as the Lord Howe Rise, Challenger Plateau and others.
Why is it mostly underwater?
In many places, the continental crust of Zealandia is considerably stretched, so it is much thinner than on other continents. Here, think about the principle of isostasy (read more about isostasy online here) and the relative densities of continental crust, oceanic crust and the mantle. In other words, the thinner area of Zealandia does not “float” as high as other continents.
What does this tell us about Earth history?
This is a great question, one partly addressed below. At the really basic level — how can a continent become so thin during rifting that it remains mostly submerged? This is a real challenge for the community that studies plate tectonics.
Why is Zealandia interesting for climate research?
One of the great problems in current Earth Science literature is the Early Eocene, about 50-53 million years ago (Ma).
