Ancient underwater sandstorms and lost cities

10 June 2003


Federal Member for Solomon, David Tollner, today welcomed to Darwin a team of explorers from Geoscience Australia, revealing amazing discoveries from a month long voyage in the Gulf of Carpentaria.

"The Gulf of Carpentaria is an important marine region and falls within the scope of plans for Australia's next regional marine resource management area," Mr Tollner said.

"Geoscience Australia's discoveries will be of significant importance to environmental and marine resource managers."

Mr Tollner said the scientific expedition discovered remarkable features in the Gulf including ancient underwater sandstorms and previously unknown reefs.

"The original plan of the expedition was to find out about sediment movement from rivers into the Gulf and how they then move on into deeper waters.

"But the team discovered that much of the sediment seen moving in the Gulf from satellite images was in fact ancient sands and silts, rather than new sediments from nearby river systems," he said.

Dr Peter Harris, expedition chief scientist from Geoscience Australia said the movements of the ancient sediments were much like underwater sandstorms.

"The Gulf is three times bigger than Tasmania and extremely flat, with only 80m from the top of the highest island to the bottom of the deepest seafloor," he said.

"Surprisingly we found two previously unknown types of reefs, at about 30 metres depth, in the South Eastern part of the Gulf. We also discovered an enormous living coral reef in the middle of the Gulf," he added.

"The 100 square kilometre reef supports a thriving array of sea-life including soft sponges, corals and shellfish. The reef looks like a lost city, with flat top and sheer sides on our echo-sounder.

"Based on our studies, we expect that reefs are far more widespread in the Gulf than had previously been suspected. It seems as though they have existed in the Gulf at different times over the last 100,000 years."

The samples and data collected on the voyage will be sent to Canberra where they will be analysed in Geoscience Australia's laboratories and studied over the next couple of years.

"Although we have made good progress with processing data aboard the Southern Surveyor, there is still a lot of work to be done to get a more complete picture of the Gulf of Carpentaria."

Mr Tollner said the Geoscience Australia team will further analyse the sediment, water column and other samples taken during the survey.

Topic contact: media@ga.gov.au Last updated: October 4, 2013