Antarctica phase IV (1997-2000)
Antarctic
shelf-slope dynamics: an innovative geophysical approach
Promotors
Professor Marc De Batist
Universiteit Gent
Renard Centre of Marine Geology
Krijgslaan 281, S8
B-9000 GENT
Phone: +32 (0)9 264 45 87
Fax: +32 (0)9 264 49 97
E-mail: marc.debatist@rug.ac.be
Dr Jean-Pierre Henriet
Universiteit Gent
Renard Centre of Marine Geology
Krijgslaan 281, S8
B-9000 GENT
Phone: +32 (0)9 264 45 85
Fax: +32 (0)9 264 49 97
E-mail: jp.henriet@rug.ac.be
Topics
The purpose of this research is the geophysical
study - at very high-resolution - of the internal structure
and evolution of Antarctic continental margins, in order to
better understand the relation between, on the one hand, the
dynamics of the ice cap and, on the other hand, the processes
of sedimentary deposition and remobilisation on the continental
slope.
It aims at exploiting in an optimal way the
seismic-reflection using large-band sources, like the "sparkers", which
were used successfully within the framework of the studies
carried out on the large lakes and more recently also on the
European continental terraces.
Goals
- In accordance with the recommendations of SCAR/ANTOSTRAT,
the research is centred on a number of specific scientific
objectives:
- on the shelf even :
analysis of the possible sedimentary residual deposits
like potential witnesses of smaller pulsations of the
ice cap, which would not have reached the edge of the
plate itself;
- on the outer part of the shelf and the higher
parts of the continental slope :
the space relation between the zones of progradation
of the "through-mouth-fans",
deposited in front of the discharge system of large ice flows;
- the space
and chronological relative relation between the deposits on the
continental slope even and those of the base of the slope;
- the space
and chronological relative relation, at large scale, between instabilities
("debris flows")
on the continental slope and the normal growth of the "through-mouth-fans",
in order to be able to determine whether these processes
are phased or outphased.
- With the aim at being able to project these processes in
an optimal way on an absolute chronology of the glacial evolution
of the Antarctic margins, the above-mentioned efforts of
research - within the framework of the operational possibilities
- will follow upon the new phase of the ODP Antarctic activities
planned for the forthcoming years.
- Regarding methodology, these scientific objectives imply
the development of a technique of seismic-reflection able
- in polar water - to preserve the optimal characteristics
of broad band as well as a maximum signal-to-noise ratio
in the useful bandwidth. To this end, it is necessary to
let towel at least one of the components of the seismic system
on some 300 meters under the surface of water, in combination
with a surface "streamer" when the atmospheric
conditions allow it. In a second step, one will also aim
the immersion of a "sparker" source, which implies
the study of the behaviour of a "sparker" system
within the framework of a "subtow" configuration
with an significant length of cable.
- A detailed attention will be given to the examination of
the possibilities of valorization of this new methodology,
in particular in the field of geotechnics of the sites located
on the continental slope (preparation
of drilling sites, study of ground instabilities).
Related Projects