Scientists on Friday set sail on an expedition to solve the mysteries of the "lost continent" Zealandia, an underwater landmass bigger than the Indian subcontinent, located to the east of Australia.
Zealandia, a five million square kilometre region submerged under the Pacific Ocean, was once part of the Gondwana super-continent but broke away some 75 million years ago.
The drill ship JOIDES Resolution is undertaking the two-month expedition to Zealandia and the Pacific 'Ring of Fire' which is a hotspot for volcanoes and earthquakes.
Professor Neville Exon from Australian National University (ANU) said the expedition would help scientists better understand the major changes in the global tectonic configuration that started about 53 million years ago as the 'Ring of Fire' came into existence.
"Zealandia, including today's Lord Howe Rise, was largely part of Australia until 75 million years ago, when it started to break away and move to the northeast. That movement halted 53 million years ago", said Exon from the ANU Research School of Earth Sciences.
Scientists will study the cores on board and onshore to address problems in fields such as climate and oceanographic history, extreme climates, sub-seafloor life, plate tectonics and earthquake-generating zones, and the dynamics of island arcs and ocean basins.
Zealandia covers five million square kilometres, and extends from south of New Zealand northward to New Caledonia and west to the Kenn Plateau off Rockhampton.
Researchers said the drill ship would collect five kilometres of sediment to discover how a region hundreds of kilometres east of Australia had behaved during the past 53 million years.
"The continental crust of Zealandia was thinned by stretching before it separated from Australia so that it lies lower than Australia", said Professor Rupert Sutherland from Victoria University of Wellington in New Zealand.
"Zealandia's continental crust is thicker than the surrounding oceanic crust, and so it lies higher than that", said Sutherland.
Professor Jerry Dickens from Rice University in the US said the region was a vital area to study the changes in global climate and oceanography.
"As Australia moved north and the Tasman Sea developed, global circulation patterns changed and water depths over Zealandia fluctuated. This region was important in influencing global changes", said Dickens.
When the ship docks in Hobart at the end of September, preliminary results of the expedition will be provided, researchers said.
