[ad_1]
You might think you know all the continents, but what about Zealandia?
In 2017, a previously unknown contingent was discovered off the coast of New Zealand, making headlines around the world.
Zeelandia, known as Te Riu-a-Māui in the Maori language, it covers more than 5 million square kilometers, which is twice the size of the Indian subcontinent.
You might be wondering why, then, it wasn’t discovered sooner.
The reason is that 95 percent of its surface is submerged under the southwestern Pacific Ocean, disappearing long before humans existed on Earth. On the surface you can only see a large mountain range (the two islands of New Zealand) and some small oceanic islands.
Little is known about the newly discovered continent, mainly because it is almost completely inaccessible. However, a team of geologists from around the world has produced a new geological map containing Zealandia. The map was formed using a combination of rock samples recovered from the sea and geophysical mapping methods.
Geologists discovered large sandstone formations and pebble deposits of basaltic rock, following the outer margins of Zealandia as they searched for samples.
The sandstones are thought to be around 95 million years old and contain older volcanic granite and pebbles, suggesting that when Zealandia was dry land, rivers flowing from the volcanic highlands filled tectonic basins.
The highlands were an active volcanic chain at least 30 to 50 million years earlier, but were probably eroded when the sandstone was deposited.
Geologists believe Zealandia was gradually flooded about 40 million years ago, thanks to the discovery of basalt pebbles, associated with underwater volcanism.
The study “Recognizing the geology and tectonics of the basement of North Zealand” was published in the journal Tectonics(2023).
Registerto our free weekly Indy100 newsletter
Have your say on our news democracy. Click the upvote icon at the top of the page to help advance this article in the Indy100 rankings.