Zealandia, the “lost continent” that encompasses Fresh Zealand and the French islands of New Caledonia, has been fully mapped for the first time, presenting scientists with a fresh understanding of how it developed tens of millions of years ago.
Zealandia, also known as Te Riu-a-Mui in Mori, was acknowledged as a continent for the first time in 2017 and is currently the first to have its geological composition, volcanic activity, and sedimentary features thoroughly mapped out at its edges.
This is despite the fact that the continent is almost entirely submerged, with only around 5% of Zealandia visible above sea level. The findings were published in the journal Tectonics on September 12th.
Zealandia’s total area is estimated to be 1.9 million square miles (4.9 million square kilometers). In 2019, scientists mapped the geology of a 0.6 million square mile (1.5 million square km) region of South Zealandia. These discoveries show that Zealandia stretched, twisted, and thinned as it separated from the supercontinent Gondwana between 60 and 100 million years ago.
The most recent study studied the undersea region of North Zealandia, which is between New Zealand, New Caledonia, and Australia.
The scientists determined that the separation of Zealandia and Gondwana was aided in part by a massive volcanic zone containing magnetic lava rocks that stretched the whole length of the boundary between the two land masses.
“Molten magma flooded out of cracks and fissures as the continent stretched and thinned like pizza dough,” said Nick Mortimer of the Institute of Geological and Nuclear Sciences Limited (GNS Science). This volcanic activity finally aided in the separation of Zealandia from Gondwana.
“Until now, the role of magma in the breakup of Gondwana has been underestimated,” said Wanda Stratford, a marine geophysicist at GNS Science, in a release. She said that these lavas cover an area of 100,000 square miles (250,000 square kilometers) over the continent, which is roughly the size of New Zealand.
The scientists were also able to thoroughly map out a 100 million to 250 million-year-old backbone of granite that winds through the center of Zealandia by analysing rock samples gathered from the seabed near New Caledonia.
According to GNS Science, the Zealandia map could assist in shedding light on New Zealand’s resources, environment, and natural dangers.
