Expedition yields secrets of the lost continent of Zealandia

Sept. 28 (UPI) -- After nine weeks at sea aboard the JOIDES Resolution research vessel, an international team of researchers is back with new insights into the submerged continent of Zealandia.

The long lost continent lies just east of Australia in the South Pacific, buried by 8,000 to 13,000 feet of water. During their expedition, 32 scientists from 12 different countries mapped the ancient continents' contours, drilled cores and collected rocks.

The expedition was organized by the International Ocean Discovery Program, which is partially funded by the National Science Foundation.

"Zealandia, a sunken continent long lost beneath the oceans, is giving up its 60 million-year-old secrets through scientific ocean drilling," Jamie Allan, program director in the ocean sciences division at NSF, said in a news release. "This expedition offered insights into Earth's history, ranging from mountain-building in New Zealand to the shifting movements of Earth's tectonic plates to changes in ocean circulation and global climate."

Zealandia, which is roughly the size of India, was confirmed as Earth's eighth continent earlier this year. The only visible parts of Zealandia are New Zealand and New Caledonia -- the rest of its 2 million square miles are underwater.

To retrace the history of the lost continent, scientists drilled more than 8,202 feet of sediment cores from deploying seabeds. The sediment layers -- and the thousands of animal specimens within them -- have offered new insights into the ways Zealandia's geography, volcanism and climate have evolved over the last 70 million years.

"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," Allan said.

Scientists still aren't entirely sure how Zealandia came to be. Observations from the expedition suggests the submerged continent has been dramatically shaped by the "Pacific Ring of Fire," seafloor zone characterized by intense tectonic activity.

Researchers previously believed the lost continent split from Australia and Antarctica some 80 million years ago.

"That is still probably accurate, but it is now clear that dramatic later events shaped the continent we explored on this voyage," said Rupert Sutherland, a researcher at Victoria University of Wellington and co-chief scientist on the expedition.

More insights into the history of Zealandia -- and published scientific papers -- are expected as scientists unpack the mass of data collected during their expedition in the coming year.