50 million year old volcano cluster found off Sydney coast

While searching for baby lobsters Australian research vessel discovers four extinct volcanos about 250 kilometres off coast of Sydney

Photo by: UNSW
Photo by: UNSW

Updated Jul 28, 2015

An Australian research vessel accidentally found a cluster of volcanoes with its center 248 kilometres from Sydney Harbour while using sonar to map the seafloor at a depth of 4,900 metres.

The Investigator, a 94-metre research vessel belonging to the Commonwealth Scientific and Industrial Research Organisation (CSIRO), was on a mission to search for nursery grounds of larval lobsters and fishes.

“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 off Sydney was a hotspot for lobster larvae at a time of the year when we were not expecting them,” said Professor Iain Suthers from the University of New South Wales.

The cluster, containing four extinct volcanos, is 20 kilometres long and six kilometres wide. The largest of four caldera – craters formed when a volcano erupts – is 1.5 kilometres across the rim and 700 metres above the sea floor.

Caldera volcanoes

According to Professor Richard Arculus, an igneous petrologist and volcano expert at the Australian National University, these volcanoes are important since “they are like windows into the seafloor.”

“They tell us part of the story of how New Zealand and Australia separated around 40-80 million years ago and they’ll now help scientists target future exploration of the sea floor to unlock the secrets of the Earth’s crust,” Professor Arculus said.

The Investigator begun its research voyage from Brisbane on June 3 with 28 scientists from various Australian universities on board and concluded on June 18 in Sydney.