A collection of extinct volcanoes up to 50 million years old has been discovered just off the coast of Sydney, some 4.9 kilometres under water.
The long-extinct volcanoes were discovered by the CSIRO’s new research ship, the Investigator, and scientists on board weren’t even looking to find ancient geological points of significance.
The cluster of volcanoes are 20km long and some 6km wide, and the four volcanoes seen in the image are known as calderas, which form after an eruption, and the land around them collapses. This forms the well-known crater formation that we see above land as well.
The largest volcano is 1.5 kilometres wide and rises up 700m from the sea bed.
Scientists onboard the Investigator were actually searching for larval lobsters – and were successful – but also found volcanoes around 248 kilometres off Sydney’s harbour.
Chief scientist for the voyage, UNSW marine biologist Professor Iain Suthers, said in a media release that the team were delighted.
“The voyage was enormously successful, not only did we discover a cluster of volcanoes on Sydney’s doorstep, we were amazed to find that an eddy [swirling movement of water] off Sydney was a hotspot for lobster larvae at a time of the year when we were not expecting them,” said Professor Suthers.
The new vessel allows researchers to see further down into the sea floor than ever before.
“The sonar on the previous Marine National Facility research vessel, Southern Surveyor, could only map the sea floor to 3,000m, which left half of Australia’s ocean territory out of reach,” Professor Richard Arculus from the Australian National University said.
“On board the new MNF vessel, Investigator, we have sonar that can map the sea floor to any depth, so all of Australia’s vast ocean territory, is now within reach and that is enormously exciting.”
The finding is expected to help understand the Earth’s crust, and the story of how New Zealand and Australia separated millions of years ago.
The research voyage is carrying 28 scientists from UNSW, Latrobe University, the University of British Columbia, the University of Sydney, the University of Auckland, the University of Technology Sydney and Southern Cross University.
Image via CSIRO