Coasts and marine

The AUSCAN Voyage

The Marion Dufresne

To carry out the detailed scientific work of the AUSCAN voyage, the National Oceans Office commissioned the ship Marion Dufresne of the French Polar Institute.

It was particularly appropriate that the ship will be departing from Hobart for the Murray Canyons exploration. Marion Dufresne, after whom the ship was named, was the French explorer who reached Tasmania before the English and the first European to make contact with Tasmania’s Indigenous population.

Marion Dufresne is France’s largest oceanographic research vessel (120 m long) and was specifically designed for work in the extreme sea and weather conditions of the Southern Ocean. It carries a wide range of advanced oceanographic, geophysical and geological equipment. Among its arsenal of research tools are two that place this vessel at the forefront of global marine research - (i) its giant piston corer ‘Calypso’ capable of recovering deep sea sediment cores 60 m long, and (ii) its Thomson-Marconi TSM 5265 multi-beam sonar swath-mapper which produces high-resolution bathymetric and backscatter images of the seafloor at 13 knots across a swath 20 km wide in deep water. Both sets of equipment are vital to the AUSCAN program.

Some more details on the Marion Dufresne:

The Murray Canyons

What are the Murray Canyons?

The Murray submarine Canyons are a vast system of deep-sea canyons about 60 km south of Kangaroo Island. Many Australians don’t realise this stretch of ocean is home to an underwater geological feature that’s bigger than the Grand Canyon and home to a vast range of fauna species. The main canyon is 4600m deep – that’s more than twice as deep as Mt Kosciuszko is high and the whole canyon system is among the most extensive and large in the world.

Some of the canyon cliffs are up to 2km high and the continental slope in the area is steeper and more rugged than anywhere else on the Australian margin. Individual canyons have not been named, despite their enormous size and relative closeness to population centres. The canyons were partly mapped in 2000 during the AUSTREA-1 multibeam survey conducted by Geoscience Australia and commissioned by the National Oceans Office and Environment Australia.

How did the canyons form?

The rugged continental slope, with its steep cliffs and deep valleys, is the crustal scar that was left when Australia tore away from Antarctica 70 million years ago and moved north by continental drift. Since then, the valleys have become deeply incised by sediment flowing down the slope. In the case of the Murray Canyons, their geographic region has, for the past few million years, lain at the outlet of the Murray-Darling river system. Sediment from inland has been deposited at the River Murray mouth and along the Coorong. The sediments deposited in the canyons over millions of years provide a record of changes in climate, vegetation type and general environment – a sort of a time capsule of the changes to the area during significant climate changes of the past million years.

What lives in the Murray Canyons?

The Murray Canyons could be home to sperm and beaked whales, giant squid and possibly endemic and previously unknown bottom-dwelling organisms. There is even the chance that new species could be found at the deep levels.

Organisers of the AUSCAN Voyage

The AUSCAN (For AUStralian CANyons) voyage was funded by the National Oceans Office (which is now part of the Marine Division of the Department of the Environment and Heritage) and managed by Geoscience Australia  – two Commonwealth government departments with a commitment to increase understanding of Australia’s ocean territory. It also involved input and cooperation from the French Polar Institute , Australian National University  and South Australian Research and Development Institute .

The Marion Dufresne

The Marion Dufresne

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