HR: 17:25h
AN: PP54A-06    [Abstracts]
TI: The George V Land Continental Margin (East Antarctica): new Insights Into Bottom Water Production and Quaternary Glacial Processes from the WEGA project
AU: * Caburlotto, A
EM: acaburlotto@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante, 42/c, Sgonico, 34010 Italy
AU: De Santis, L
EM: ldesantis@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante, 42/c, Sgonico, 34010 Italy
AU: Lucchi, R G
EM: rlucchi@ogs.trieste.it
AF: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Borgo Grotta Gigante, 42/c, Sgonico, 34010 Italy
AU: Giorgetti, G
EM: giorgettig@unisi.it
AF: Dipartimento di Scienze della Terra - Universita' di Siena, Via Laterina, 8, Siena, 53100 Italy
AU: Damiani, D
EM: damiani@unisi.it
AF: Dipartimento di Scienze della Terra - Universita' di Siena, Via Laterina, 8, Siena, 53100 Italy
AU: Macri', P
EM: macri@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia - INGV, Via di Vigna Murata, 605, Roma, 00143 Italy
AU: Tolotti, R
EM: tolotti@dipteris.unige.it
AF: Dipartimento per lo Studio del Territorio e delle sue Risorse - Universita' di Genova, Corso Europa, 26, Genova, 16132 Italy
AU: Presti, M
EM: massimo@ncmr.gr
AF: Hellenic Centre for Marine Research - Institute of Oceanography, Athinon-Souniou km 46,5, Anavyssos, 19013 Greece
AU: Armand, L
EM: Leanne.Armand@csiro.au
AF: CSIRO Marine Research - Sustainable Marine Ecosystem in the South East, GPO Box 1538, Hobart, 7001 Australia
AU: Harris, P
EM: peter.harris@ga.gov.au
AF: Geoscience Australia - Marine and Coastal Environment, GPO Box 378, Canberra, 2601 Australia
AB: The George Vth Land represents the ending of one of the largest subglacial basin (Wilkes Basin) of the East Antarctic Ice Sheet (EAIS). Furthermore, its coastal areas are zone of significant production of High Salinity Shelf Water (HSSW). Piston and gravity cores and high resolution echo-sounding (3.5 kHz) and Chirp profiles collected in the frame of the joint Australian and Italian WEGA (WilkEs Basin GlAcial History) project provide new insights into the Quaternary history of the EAIS and the HSSW across this margin: from the sediment record filling and draping valleys and banks along the continental shelf, to the continuous sedimentary section of the mound-channel system on the continental rise. The discovery of a current-lain sediment drift (Mertz Drift, MD) provides clues to understanding the age of the last glacial erosive events, as well as to infer flow-pathways of bottom-water masses changes. The MD shows disrupted, fluted reflectors due to glacial advance during the LGM (Last Glacial Maximum) in shallow water, while undisturbed sediment drift deposited at greater water depth, indicates that during the LGM the ice shelf was floating over the deep sector of the basin. The main sedimentary environment characterising the modern conditions of the continental rise is dominated by the turbiditic processes with a minor contribution of contour currents action. Nevertheless, some areas (WEGA Channel) are currently characterised by transport and settling of sediment through HSSW, originating in the shelf area. This particular environment likely persisted since pre-LGM times. It could indicate a continuous supply of sedimentary material from HSSW during the most recent both glacial and interglacial cycles. This would be consistent with the results obtained in the continental shelf suggesting that the Ice Sheet was not grounding over some parts of the continental shelf. Furthermore, the comparison of the studied area with other Antarctic margins indicate that, contrary to what happens on the Antarctic Peninsula margin, the relation between the Quaternary sedimentation and the glacial - interglacial cycles are less evident in the lithofacies observed on the continental rise area. This characteristic suggests a different glacial dynamic along the Wilkes Land continental margin that is less sensitive to the small climatic changes, with respect to the western (Antarctic Peninsula) margin.
DE: 9310 Antarctica
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting