There are parts of planet Earth that are still a mystery to human beings. Recently, a team of scientists has shed some light on one of the areas that still kept an aura of mystery: Zealandia.
Also known as the New Zealand continent, it is an almost submerged surface of land that sank after separating from Asia between 60 and 85 million years ago and from Antarctica between 130 and 185 million years ago.
The crust of this eighth continent was known to be thinner than that of most continents, although thicker than oceanic crust. It was formed during the fracture of Gondwana, when the crust was thinned and stretched. In addition, it has been confirmed that Zealandia was home to a varied fauna and flora in the past, thanks to evidence such as pollen spores from land plants and remains of shallow sea creatures, now hidden under the ocean.
Now, science has managed to shed light on certain aspects of Zealandia. As reflected in the study Reconnaissance of the geology and tectonics of the subsurface of North Zealand - published in the journal Tectonics of the Advancing Earth and space science and led by researchers from GNS Science of New Zealand - researchers have completed the mapping and have created a detailed map of the northern two-thirds of Zealandia to study how this continent formed, thus completing the documentation of the almost three million square kilometers of submerged land mass.
Researchers analyze the geochemistry of the rock after collecting materials to understand the underwater composition of Zealandia. The scientists found sandstone dating back about 95 million years, from the Late Cretaceous, and a combination of granite and volcanic pebbles that are up to 130 million years old, also from the Late Cretaceous. The basalts are more recent, with an age of approximately 40 million years, during the Eocene.
Zealand was an exceptionally long and narrow continent, from New Caledonia in the north to beyond the subantarctic islands of New Zealand in the south. New Zealand is today the largest portion above sea level, followed by New Caledonia and its surrounding islands. Most of it (around 90%) ended up submerged approximately 23 million years ago under the Pacific Ocean.
At its greatest extent, it would have had an area of 4.9 million square kilometers, larger than Greenland or India today, or more than half the size of Australia.
