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‘Lost Continent’ Expedition Provides Clues to Earth’s History

Scientists set out to study the region known as 'Zealandia.'

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A group of 32 scientists spent two months exploring an unknown region called Zealandia that lies just east of Australia. What they found dates back millions of years and could provide clues to the Earth’s history, National Geographic reports.

The region is about the size of India, but sits 8,000 to 13,000 feet below the sea. The researchers drilled into the seabed to retrieve 8,202 feet of sediment cores, National Geographic writes. These cores showed specimens dating back to millions of years.

Gerald Dickens, the expedition’s co-chief scientist, said in a press release that several hundred fossil species were identified, National Geographic reports. One of the most significant findings was that Zealandia was shallower then. The scientists can tell this because they discovered shells of organisms that lived in warm shallow seas, and spores and pollen from land plants, National Geographic writes.

It is estimated that Zealandia broke off Australia 40 to 50 million years ago. Experts disagree on whether or not to qualify it as a continent.

Northwestern geologist Christopher Scotese told National Geographic that the region was “continental but not a continent,” because a continent is a landmass above and surrounded by water.

The region sits above two tectonic plates, the Australian plate and the Pacific plate, National Geographic reports, and when he broke off, the Pacific plate got stuck under the Australian plate. This created a “subduction zone” and makes it one of the several large features in the “Ring of Fire,” which is a region that has a lot of seismic and volcanic activity.

Jamie Allen, the program director for the National Science Foundation’s Division of Ocean Sciences, told National Geographic that this is a “crucial part of our history” because the land split from Australia for reasons we don’t understand. The data the scientists collected will be like “tape recorders” of the region’s history, National Geographic writes. Lots can be discovered from the data, like how warm the water was at certain points in time, and deep or shallow the landmass was, and could also point towards a better understanding of how plants and animals were spread out in the Pacific in the past.

“If you have an understanding of why Earth’s climate changed in the past, that helps you model it for the future,” Allen said to National Geographic. 

Read full story at National Geographic