Zealandia, the lost continent that sits underwater

Zealandia, also known as the New Zealand continent or Tasmantis, is an almost entirely submerged mass of continental crust that subsided after breaking away from Gondwanaland 79-83 million years ago. The name and concept for Zealandia was proposed by Bruce Luyendyk in 1995.

The boot-shaped region, about the size of greater India, contains New Zealand ana New Caledonia, an island to the north. Most of Zealandia, about 94% of it, is submerged underwater, according to the findings published by The Geological Society of America.

A team of New Zealand-based researchers made the discovery, which they described as a “gradual realization” based on reassessing years of data. The researchers tested Zealandia’s attributes against four characteristics common to continents. They concluded Zealandia “is not a collection of partly submerged continental fragments” but rather, is a “coherent” continent.

According to expedition co-cheif scientist Gerald Dickens of Rice University in Huston, Texas, Zealandia expedition scientists made signigicant new fossil discoveries, proving that Zealandia was not always as deep beneath the waves as it is today. He said:

More than 8.000 specimens were studied, and several hundred fossil species were identified.
The discovery of microscopic shells of organisms that lived in warm shallow seas, and of spores and pollen from land plants, reveal that the geography and climate of Zealandia were dramatically different in the past.

He also said that the new discoveries show that the Pacific Ocean’s encircling Ring of Fire, where there are frequent earthquakes and powerful volcanic eruption, had a role in causing Zealandia’s submersion in the ocean depth and volcanic activity, which buckled the seabed of Zealandia.
A team led by James Scott at the University of Otago in Dunedin, New Zealand, explored the geological history of Zealandia, a mostly-submerged landmass in the southwest Pacific Ocean that some researchers claim is the planet’s eight continent. Zealandia began to take shape around 85 million years ago, making it relatively young.

Scott and his colleagues analysed the chemestry of rocks from New Zealand’s South Island and several nearby islands. These rocks include fragments from the continental rood underlying Zealandia.
A team determined that these rocks are chemically similar to those beneath the Archean crust. The work indicates that virtually the same processes behind the formation and stabilization of the oldest continents also helped Zealandia to take shape.

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