Zealandia

Zealandia, called Te Riu-a-Maui in Maori and sometimes known as Tasmantis, is a vast, almost entirely submerged mass of continental crust in the southwest Pacific that broke away from the ancient supercontinent Gondwana between 83 and 79 million years ago; geologist Bruce Luyendyk proposed the name and the concept of Zealandia as a coherent continent in 1995. The landmass covers roughly 4,900,000 square kilometers, comparable in area to Australia, but about 94 percent of it lies submerged beneath the Pacific Ocean, and a 2021 study of its rock suggested parts of its crust are more than a billion years old, roughly twice the age once assumed. Zealandia has been subsiding since breaking away from Gondwana, possibly becoming fully submerged by about 23 million years ago, driven partly by subduction of the Pacific Plate; today its largest exposed portions are the islands of New Zealand and New Caledonia, along with small Australian territories including Lord Howe Island and Norfolk Island, and it supports a population of roughly 5.4 million people.