Zealandia comes to light

The mostly sunken continent of Zealandia, which surrounds New Zealand, used to be closer to the surface of the sea and had a very different climate in the past, researchers believe. A team of 32 scientists from 12 countries has just finished a nine-week voyage to study the undersea continent, drilling deep into the seabed at six sites in water depths of more than 1250 metres.

More than 8000 fossil specimens were studied, with several hundred species 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,’’ expedition co-chief scientist Gerald Dickens, of Rice University in the US, said.

The new discoveries showed the formation 40 to 50 million years ago of the Pacific ring of fire, an active seafloor zone along the perimeter of the Pacific Ocean, caused dramatic changes in ocean depth and volcanic activity and buckled the seabed of Zealandia. The fossil discoveries proved Zealandia - now more than 1km under the sea - was not always as deep under the waves as it was now, Dickens said.

Victoria University of Wellington professor Rupert Sutherland, who was also co-chief scientist of the expedition, said researchers had believed Zealandia was submerged when it separated from Australia and Antarctica about 80 million years ago.’’