Zealandia has recently been given the status of a continent by several geologists who say that the long lost continent is submerged under water. While there is no formal recognition of the same by the New Zealand government, which is the major habitable administration on Zealandia; there is, however, wide interest in the media about the continent.
The continent is largely made up of two parallel ridges, separated by a failed rift. The ridges rise above the sea floor with infrequent rocky islands rising above sea level. Scientists identify two main portions of the continent, North Zealandia (or Western Province) and South Zealandia (or Eastern Province).
Compared to other continents it has much wider and deeper continental shelves. The highest point of Zealandia is Aoraki–Mount Cook at 3724 m.
The region has elevated bathymetry relative to surrounding oceanic crust, diverse and silica-rich rocks, and relatively thick and low-velocity crustal structure. Volcanism is widespread across Zealandia but generally of low volume.
- Locatation: It is located on the southwest Pacific Ocean mostly surrounding, in what is the current land mass of New Zealand and its adjoining islands.
- Size: The total area is estimated to be approximately 4,920,000 square km of which 93% remains submerged below the Pacific Ocean. In terms of size, it is the world’s largest current micro-continent, about half the size of the Australian continent.
- Areas fall under Zealandia
- New Zealand
- New Caledonia
- Norfolk Island
- Lord Howe Island Group
In a study published in the Geological Society of America’s Journal, the authors explain continent-making criteria, of which Zealandia fulfills the requirements. Here’s a summary of their summary of the four key attributes of continents and assess how Zealandia meets these criteria.
Zealandia is everywhere substantially elevated above the surrounding oceanic crust. The main difference with other continents is that it has much wider and deeper continental shelves than is usually the case.
By itself, relatively high elevation is not enough to establish that a piece of crust is continental, but looking at the geology of Zealandia puts it into continent turf. To make a long story short, the authors note: “Essential geological ground truth for Zealandia is provided by the many island outcrop, drill core, xenolith, and seabed dredge samples of Paleozoic and Mesozoic greywacke, schist, granite, and other siliceous continental rocks that have been found within its limits.”
Zealandia’s crustal structure is atypical of normal oceanic crust. And while most of its crust is thinner than that of most continents, it is nonetheless thicker than even the thickest crust of the ocean basins.
Limits and Area
- There is a long discussion about continent-ocean boundaries and well-defined geologic and geographic limits and from which it is to be concluded that Zealandia is large enough and well-defined enough to be termed a continent.
- The main author of the paper, New Zealand geologist Nick Mortimer, says scientists have been researching data to make the case for Zealandia for more than two decades.
- “The scientific value of classifying Zealandia as a continent is much more than just an extra name on a list,” the researchers write. “That a continent can be so submerged yet unfragmented” makes it useful for “exploring the cohesion and breakup of continental crust.”