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Tolotti, R.
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Tolotti, R.
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- PublicationRestrictedWilkes Land Late Pleistocene diatom age model: From bio-events to quantitative biostratigraphyA new method merges conventional and quantitative biostratigraphic approaches, supported by magnetic polarity data, to develop a chronological framework for sediment core MD03-2595 retrieved on the continental rise off Wilkes Land, East Antarctica before proceeding to paleoceanographic and paleoclimatic analysis. This combined method helped to identify climatic cycles, highlight stratigraphic discontinuities and reworking, and assess regional sedimentological and diatom biostratigraphic evolution. Core MD03-2595 spans the last 0.8 Ma, from the Mid Pleistocene Transition (MPT) to the Early Holocene. A hiatus including Marine Isotope Stages (MIS) 19, 18 and 17 was identified, and a decreasing trend in sediment accumulation rates from MIS 16 to the Holocene was observed. This quantitative diatom biostratigraphic dataset, placed in its own sedimentological and paleomagnetic context, provides new information regarding the paleobiogeographic distribution and ecological responses of biostratigraphically significant diatom species, such as Thalassiosira elliptipora and T. fasciculata, for the Matuyama–Brunhes (M–B) transition, and Actinocyclus ingens, Hemidiscus karstenii and Rouxia spp. for the middle and late Pleistocene diatom biozonation.
272 1 - PublicationRestrictedSedimentary processes on the Wilkes Land continental rise reflect changes in glacial dynamic and bottom water flow(2010-06)
; ; ; ; ; ;Caburlotto, A.; Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, OGS, Borgo grotta Gigante 42/c, 34010 Sgonico, Italy ;Lucchi, R. G.; Department D’Estatrigrafia, P. i Geocie´nces Marines, Universitat de Barcelona, C/Martı´ i Franque`s, s/n, 08028 Barcelona, Spain ;De Santis, L.; Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, OGS, Borgo grotta Gigante 42/c, 34010 Sgonico, Italy ;Macrì, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tolotti, R.; Dip. Te. Ris., Universita` degli Studi di Genova, Corso Europa 26, 16132 Genoa, Italy; ; ; ; Four sediment cores were analysed in order to determine the sedimentary processes associated with the channel-ridge depositional system that characterise the George V Land continental margin on the Wilkes Land. The sedimentary record indicates that the WEGA channel was a dynamic turbiditic system up to M.I.S. 11. After this time, the channel became a lower-energy environment with sediments delivered to the channel through high-density bottom waters that we identify to be the high salinity shelf waters (HSSW) forming on the shelf area. The HSSW entrains the fine-grained sediments of the shelf area and deliver them to the continental rise. The biostratigraphy and facies of the sediments within the WEGA channel indicate that the HSSW down flow was active also during last glacial. The change from a turbiditic system to a lowenergy bottom current system within the WEGA channel likely reflects a different ice-flow pattern, with ice-sheet reaching the continental shelf edge only within the ice trough (ice stream).456 55