Frontiers and Opportunities in Antarctic Geosciences * Certosa di Pontignano * 29-31 July 2004
Revision of the Maps of the Main Interpreted Seismic Unconformities
in the Victoria Land Basin
C. SAULI*, G. BRANCOLINI, L. DE SANTIS, N. WARDELL
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) -Trieste, Italy
*Corresponding author (csauli@ogs.trieste.it)
The Ross Sea, wide epicontinental basin on the pacific margin of the Antarctic continent, has been an active rift system
since Mesozoic times. Its structure is asymmetric with the rift shoulder on the western side (Transantarctic Mountains)
rapidly uplifted during the Cenozoic.
The depression of the Victoria Land Basin (VLB), adjacent to the TAM, develops between cenozoic volcanic provinces of
the Ross Island and Cape Washington, also probably extending below the Ross Ice Shelf to the south. The Victoria Land
Basin is filled by a thick (10-14 km) sedimentary section, strongly affected by tectonics, magmatic intrusions and glacial
erosion.
Stratigraphic and isopach maps for the eigth principal regional unconformities and seismic sequences in the Ross Sea were
produced by the Ross Sea Regional Working Group of the Antarctic Offshore Acoustic Stratigraphy project
(ANTOSTRAT) (Brancolini et al., 1995). Despite the large volume of data utilized for mapping the main unconformities in
the entire Ross Seas, one of the questions that is still debated is the total thickness and the age of the sediments in the
Victoria Land Basin. The recent results of Cape Roberts drilling in McMurdo Sound in the VLB, that sampled more than
800 m of Cenozoic sedimentary cover, overlaying the clastics of the Beacon Supergroup (Devonian), can produce more
insight into the analysis of the VLB sedimentary content.
Davey et al. (2000) and Henrys et al. (2001) correlated the CRP drilling to the surrounding seismic data. In this work we
present a project (VILMAP) whose target is a comprehensive review of the entire seismic dataset in the VLB, based on the
more recent geologic data from Cape Roberts and taking advantage of the reprocessing of some seismic profiles in key
areas.
The project will consist of four phases: 1) a review of the seismic lines (MCS and SCS) currently available; 2) a successive
phase of reprocessing of selected seismic lines; 3) a third phase of interpretation; 4) a final phase of producing maps.
Reprocessing of the data will be done in order to improve the resolution and the reliability of the interpretation. The final
product of the project is expected to be updated digital maps of the main interpreted unconformities and isopach maps of the
seismostratigraphic units.
The study is focused in particular on the distribution, geometries and ages of the main sedimentary bodies that have been
deposited in the area, with the aim of providing a more solid base for the reconstruction of the still not well known
geodynamic evolution of the Victoria Land Basin.
REFERENCES
Brancolini G., Busetti M., Coren F., De Cillia C., Marchetti M., De Santis L., Zanolla C., Cooper A.K., Cochrane G.R., Zayatz I., Belyaev V., Knyazev M.,
Vinnikovskaya O., Davey F.J. and Hinz K., 1995. "ANTOSTRAT Project, seismic stratigraphic atlas of the Ross Sea, Antartica". In: Cooper A.K.,
Barker P.F. and Brancolini G. (Editors), Geology and Seismic Stratigraphy of the Antarctic Margin. Antarctic Research Series, AGU Washington
D.C., vol. 68.
Brancolini G., Cooper A., Coren F., 1995. Seismic facies and glacial history in the Western Ross Sea
(Antarctica). In: Geology and Seismic Stratigraphy of the Antarctic Margin, Antarctic Research
Series, vol. 68, edited by A.K. Cooper, P.F. Barker and G. Brancolini, AGU Washington D.C., pp.
209-234.
Davey, F. J., Brancolini, G., Hamilton, R. J., Henrys, S. A. , Sorlien, C. C., and Bartek, L. R., 2000. A Revised correlation of the seismic stratigraphy at
the Cape Roberts drill sites with the seismic Stratigraphy of the Victoria Land Basin. Terra Antartica, 7, 215-220.
Henrys S.A., Bücker C.J., Niessen F. and Bartek L.R. 2001: Correlation of Seismic Reflectors with the CRP-3 Drillhole, Victoria Land Basin, Antarctica.
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