Murray Canyons
This animation is
largely based on data collected during a major research expedition called
AUSCAN (AUStralian CANyons) conducted over a 3-week period in January-March
2003 along Australia’s southern margin (Figure 1).
The research vessel used was the 120-m Marion Dufresne of the French Polar
Institute IPEV (Institut Polaire Français - Paul-Emile Victor).
The ship carries a range of geophysical, sampling and oceanographic equipment,
but particularly important to the AUSCAN program were the ship’s
giant piston corer ‘Calypso’ capable of recovering deepsea
sediment cores up to 60 m long, and its Thales Sea Falcon 11 multibeam
sonar swath-mapper which produces high-resolution bathymetric and backscatter
images of the seafloor at speeds of up to 15 knots across a swath up to
20 km wide in deep water.
The objectives of the AUSCAN cruise were:
• to continue swath-mapping of the southern margin
of Australia and to collect geophysical data, as an aid to bioregionalisation,
geological framework studies, Regional Marine Planning and the establishment
of Marine Protected Areas.
• to sample the Murray Canyons area, south of Kangaroo Island, to
help establish its present oceanographic, sedimentological and biological
character and, through long cores, to examine the past history of the
canyons and better understand the late Quaternary climate and environmental
history of the Murray-Darling Basin.
The Murray Canyons, a special focus of the investigation, are spectacular
submarine topographic features with complex and extensive channel systems
and 2-km high cliffs. The continental slope here, formed when Australia
split from Antarctica 65 million years ago, is steeper than anywhere else
on the Australian continental margin, dropping from 200 m depth at the
shelf edge to more than 5000 m over a distance of only 40 km.
The AUSCAN cruise was conducted as an international cooperative research
program, with scientists from Australian, French, German and US academic
and government marine research agencies taking part. IPEV was the main
French organisation involved, while Australian institutions include Geoscience
Australia, the Australian National University (ANU), SARDI (South Australian
Research & Development Institute) and the National Oceans Office.
The National Oceans Office provided major Australian funding and other
support because of AUSCAN’s direct and important relevance to current
regional marine planning and environmental management initiatives, including
development of National Bioregionalisation and the South-east Regional
Marine Plan. The AUSCAN project is being managed by Geoscience Australia
for the National Oceans Office.
