New Caledonia in geological terms is a high region of a mostly submerged continent called Zealandia. While it is around 94% under water today, in Earth's ancient past, it existed above sea level. With a total area around 4.9 million km2, what is called New Caledonia today is located in the northern portion of the continent with the islands of New Zealand occupying the south.
But what does it mean when we talk about the term 'continent'. Most people in the world recognise five to seven continents. By most accounts they are Europe, Africa, North America, South America, Asia, Antarctica, and Oceania/Australasia. But this list is a political view of the world's continents. In a geological sense, the list below are Earth's actual continents or single landmasses that stick out of the ocean floor: Europe, Asia, North America, South America, Africa, Antarctica, and Australia.
NOTE: North and South America are in fact lightly joined by the 'Isthmus of Panama' and Africa is joined to Asia by the narrow 'Isthmus of Suez'. Most scientists and gelologists do not link them as single masses because these continents are just touching each other as opposed to being part of the main continental shape.Also, Europe and Asia are often placed together as one single landmass called Eurasia.
Earth's continents including Zealandia.
Scientists now want to add a new continent to the list of world continents. Named Zealandia, this new continent lies a mere 25 km at its closest point to Australia and spans from New Caledonia in the north to further south than New Zealand. But why this continent was not recognised earlier?
In Earth's history, this continent was above sea level, but today it is mostly submerged. This explains why this discovery was recent and gradual. Modern satellite imagery played a big part in the continents discovery, butmany geologists suspected there was a continent there before that, they just couldn't prove it. The term Zealandia was first coined back in 1995, but what has changed today is the accumulated data over the last two decades that has seen Zealandia tick all four requirements that define a continent. Initially three boxes were ticked with the fouth unknown. But now that all requirements have been met, Zealandia is by definition, one of Earth's continents, Unless the rules for continents change like the definition of planets which saw Pluto demoted from planethood, Zealand is set to be recognised as one of Earth's continents.
The four main points that define a continent are:
Mortimer a geologist making the case for Zealandia explains one difference between Zealandia and the other continents.
"Most continents have a big landmass and narrow continental shelf, whereas Zealandia has a small landmass and a very wide continental shelf."
Read more: The lost continent of Zealandia →