A team of geologists proclaims that under the waters of the Pacific lies a land mass that deserves the treatment of a continent. Name: Zealandia. Location: expands from northeastern Australia to beyond southern New Zealand (see map) . Size: 4.9 million square kilometers, about two-thirds the size of Australia.
But not all Zealandia is hidden in the depths. The islands of New Zealand (in this NASA image you can see them from space) and New Caledonia are its highest elevations and its visible part.
The Continents Club
There is no scientific consensus to define what a continent is (are there five, six, seven?), But a team of geologists from New Zealand, New Caledonia and Australia argue that Zealandia has the characteristics that give it the right to belong to the select club of Africa, America, Eurasia and the others: a defined area, its own geological characteristics, a crust that is thicker than the one that surrounds it and an elevation higher than the area that surrounds it (a “relief”, we could say).
94% of Zealandia is submerged. In the work defending its existence, published by the Geological Society of the United States, it is said that this new geological entity began to separate from the supercontinent Gondwana about 100 million years ago. This rupture thinned Zealandia’s crust and caused it to collapse. Only 6% of its surface remained on water: the island of New Caledonia and the New Zealand archipelago.
The satellite view
The strongest argument for Zealandia’s existence comes from space. Satellite maps from the Earth’s gravitational field clearly show that the would-be new continent is a unique geological structure. The samples of the sea floor reveal that Zealandia is composed of the rocks that form the continental crust, and not of the volcanic rocks of the adjacent areas, typical of the marine crust.
Some scientists consider it irrelevant whether Zealandia is a continent or not; But others believe that studying their formation will help better understand how New Zealand’s endemic flora and fauna arose and developed, and that it will give geologists new clues about the birth and nature of the continents.
