Friday, 31 August 2007
5.PS-123
Late Quaternary sediment record of six glacial/interglacial cycles off the Wilkes Land - Adelie Land Coast (East Antarctica): preliminary geochemical results
Massimo Presti1, Loic Barbara2, Delphine Denis3, Xavier Crosta2, Eveline De Voos4, Marina Lipizer4, Cinzia De Vittor4, Alessandro Acquavita4, Catherine Kissel5, and Laura De Santis1. (1) Geophysics of the Lithosphere, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42/c-Sgonico, Trieste, Italy, (2) EPOC, Université Bordeaux I UMR-CNRS 5805, Avenue des Facultés, 33405 Talence Cedex, France, (3) EPOC, Université Bordeaux I UMR-CNRS 5805, Avenue des Facultés, 33405 Talence Cedex, France, (4) Istituto Nazionale di Oceanografia e Geof. Speriment. OGS, Biological Oceanography, v. Piccard, 54, 34014 - S. Croce ( TS ), Italy, (5) LSCE, CNRS, Gif-sur-Yvette, Avenue de la Terrasse, Bat 12, Gif-sur-Yvette, 91198, France
A multidisciplinary CADO-IMAGES X research cruise targeted in 2003 the Adelie Land Coast off East Antarctica (136°-140° E), laying at the seaward termination of the largest, marine-based sector of the East Antarctic Ice Sheet (Wilkes Basin) and therefore being ideal to seek for proxies of duration and mechanism of past climatic changes. A complete dataset has been acquired on core MD03-2603, a ~32 m long piston core collected on a mound along the rise, with the aim of investigating the late-Quaternary depositional environment in relation to paleoceanographic conditions. Geochemical/compositional information have been compared to isotopic, biostratigraphic and paleomagnetic data, leading to the identification of six glacial/interglacial climatic cycles. Preliminary data suggest that interglacial cycles are characterised by hemipelagic biogenic muds, deposited in sub-oxic environment. Glacial periods display instead a sequence of turbiditic and contouritic deposits, in which lateral focussing is predominant and the detrital fraction more abundant.