Summary
Data from three recent cruises on N.O. L'Atalante are used in collaboration
with AGSO to use backscatter and bathymetry data for seafloor classification,
and to reconstruct the tectonic and sedimentary history of selected areas,
also based on 3.5 kHz, seismic reflection, gravity and magnetic data.
Outcomes
The geological interpretation of backscatter imagery currently often
relies on the level of experience of the interpreter and is therefore a
subjective and time consuming method of analysis. In an effort to improve
this procedure we are developing automated imae classification routines
for the interpretation of backscatter data using artificial neural networks.
As test area we are using a survey in the Great Australian Bight
(E130º - E131º) that was conducted for Environment Australia.
This area has been declared a marine park, as it is free of anthropogenic
disturbance. It includes a range of depths (~400m – ~3500m) and seafloor
environments that can be classified and used as standards for pattern recognition
processes.
The second area analysed as part of this project is the Norfolk Basin. It is divided by a saddle located at the Norfolk ridge at 29S 168E, where Norfolk Island is the surface expression of the raised topography, and continues ESE until it reaches the Three Kings Ridge at 30S 173E. At its Western end, the ridge begins as a large bulge in the eastern edge of the Norfolk Ridge, which extends from 168E to 168.5E. At the end of this bulge, the topography drops off dramatically, and the ridge becomes less pronounced, and more defined by volcanic features. These volcanoes tend to be elongate in the saddle direction, and often have become flat-topped guyots. The nature of these volcanoes may give insight into the evolution of the Norfolk basins. The third area analysed is the South Tasman Rise and the Tasmanian shelf, based on multibeam data collected in 1994 and 1999/2000.
Sponsors
Australian Geological Survey Organization
Environment Australia
Participants
Dr. R. D. Müller, The University of Sydney
Dr. Michael Hughes, The University of Sydney
Mr. Phil Symonds, Australian Geological Survey Organization
Jonathan Bathgate, The University of Sydney, Hons student
Nik Smith, The University of Sydney, Hons student
Boris Turpeaud, The University of Sydney, Overseas visiting student
Maria Sdrolias, The University of Sydney, PhD student