The ‘lost continent’ Zealandia, which includes New Zealand and the French islands of New Caledonia, has been fully mapped in a world first, providing scientists with a new understanding of how it formed tens of millions of years ago.
It was Zealandia, known as te reo a maui in the Maori language It was first recognized as a continent in 2017 It is now the first to have its rock composition, volcanic activity and sedimentary features mapped entirely on its margins.
This is despite the continent being almost entirely underwater, with only about 5% of Zealandia above sea level. The researchers published their findings on September 12 in the journal Tectonics.
Overall, Zealandia’s area is estimated at 1.9 million square miles (4.9 million square km). In 2019, scientists drew a map Geology of South Zealandia It extends over an area of 0.6 million square miles (1.5 million square kilometers). These findings reveal that Zealandia stretched, twisted, and thinned as it separated from the supercontinent Gondwana between 60 million and 100 million years ago.
Related: Is Africa divided into two continents?
In the latest study, researchers mapped the underwater area in northern Zealandia, located between New Zealand, New Caledonia and Australia.
Scientists discovered that the separation of Zealandia from Gondwana was driven in part by a giant volcanic zone containing magnetic lava rocks, which extended along the boundary between the two land masses.
“Molten magma flowed from cracks and crevices as the continent stretched and thinned like pizza dough.” Nick MortimerA geologist at the Institute of Geological and Nuclear Sciences Limited (GNS Science) said in A statement. This volcanic activity eventually helped Zealandia separate from Gondwana.
“Until now, the role of magma in the breakup of Gondwana has been underestimated.” Wanda StratfordA marine geophysicist at GNS Science said in the statement. She added that this lava covers an area of 100,000 square miles (250,000 square kilometers) across the continent, which is approximately the size of New Zealand.
By studying rock samples collected from the sea floor near New Caledonia, scientists were also able to fully map a granite spine, between 100 million and 250 million years old, that runs through central Zealandia.
GNS Science said in the statement that the Zealandia map could help highlight New Zealand’s resources, environment and natural hazards.
“Web maven. Infuriatingly humble beer geek. Bacon fanatic. Typical creator. Music expert.”