@prefix prodottidellaricerca: . @prefix istituto: . @prefix prodotto: . istituto:CDS080 prodottidellaricerca:prodotto prodotto:ID48851 . @prefix pubblicazioni: . @prefix unitaDiPersonaleInterno: . unitaDiPersonaleInterno:MATRICOLA20147 pubblicazioni:autoreCNRDi prodotto:ID48851 . @prefix rdf: . prodotto:ID48851 rdf:type prodotto:TIPO1101 . @prefix retescientifica: . prodotto:ID48851 rdf:type retescientifica:ProdottoDellaRicerca . @prefix rdfs: . prodotto:ID48851 rdfs:label "Seismic facies and sedimentary processes on the continental rise off Wilkes Land (East Antarctica): evidence of bottom current activity. (Articolo in rivista)"@en . @prefix xsd: . prodotto:ID48851 pubblicazioni:anno "2003-01-01T00:00:00+01:00"^^xsd:gYear . @prefix skos: . prodotto:ID48851 skos:altLabel "
Donda F.1, Brancolini G.1, De Santis L.1, Trincardi F. 2 (2003)
Seismic facies and sedimentary processes on the continental rise off Wilkes Land (East Antarctica): evidence of bottom current activity.
"^^rdf:HTML ; pubblicazioni:autori "Donda F.1, Brancolini G.1, De Santis L.1, Trincardi F. 2"^^xsd:string ; pubblicazioni:paginaInizio "1509"^^xsd:string ; pubblicazioni:paginaFine "1527"^^xsd:string ; pubblicazioni:altreInformazioni "IMPACT FACTOR 2003: 1.182 TOTAL NUMBER OF Deep Sea Research CITATIONS IN 2002: 1753\nThis paper is one of the outcomes of a cooperation among OGS, CNR and other Research Institutions (Australia, Italy, and New Zealand) cooperating in the project WEGA to study the Antarctic shelf and slope systems off Wilkes Land (East Atarctica)"^^xsd:string ; pubblicazioni:numeroVolume "50"^^xsd:string ; pubblicazioni:note "IMPACT FACTOR 2003: 1.162 TOTAL NUMBER OF DSR CITATIONS IN 2002: 1753"^^xsd:string ; pubblicazioni:descrizioneSinteticaDelProdotto "This paper summarises the first results of a mucti-channel seismic survey of the Antarctic continental margin off Wilkes Land (East Atarctica) showing a complex stratigraphy and sea floor morphology related to the activity of bottom currents. Whether such bottom currents are contour prarallel or downslope remains to be ascertained. However, the paper defines areas where further investigation would be useful."^^xsd:string ; skos:note "ISI Web of Science (WOS)"^^xsd:string ; pubblicazioni:affiliazioni "1:Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Borgo Grotta Gigante, I-34010 Sgonico, TS, Italy\n2: ISMAR-IGM (CNR), VIA GOBETTI, I-40129 Bologna, Italy"^^xsd:string ; pubblicazioni:titolo "Seismic facies and sedimentary processes on the continental rise off Wilkes Land (East Antarctica): evidence of bottom current activity."^^xsd:string ; prodottidellaricerca:abstract "The slope and rise areas off Wilkes Land (East Antarctica) encompass three large-scale composite sediment ridges dissected by two broad deep-sea valleys (Jussieu Canyon\nand WEGA Channel). Large-scale depositional architecture, revealed from multi-channel seismic profiles acquired during the WilkEs Basin GlaciAl History (WEGA) cruise,\nindicates a wide temporal and spatial variability in the dominant depositional processes delivering or redistributing sediments on the slope and rise. All three sediment ridges\nare built on a flat seafloor and resulted from the growth of a thick sediment section (at least 2 km) with a depositional relief in the order of hundreds of meters on the adjacent\ndeepsea valleys. The sediment ridges show their maximum internal complexity in areas shallower than 3000m, where they are also substantially thicker (as much as 1-1.5 s. in\ntwo-way travel time). High amplitude sediment waves (typically 20-30m and up to 50-70m) have wavelengths ranging from 1500 to 3500m and occur in the deepest sectors\nof the continental rise, where the sediment ridges toe out. In the lower rise, the sediment waves display a consistent decrease in wavelength with increasing water depth. On\nseismic profiles, the relief of the sediment waves decreases from older to younger sequences, possibly indicating a decrease in bottom current intensity throughout their\nformation. Sediment waves occur also at the seafloor, which is dominated elsewhere by irregular topography and widespread evidence of erosion. However, no conclusion\ncan be drawn on the possible modern activity of these large-scale bedforms.\n\nIn shallower, upper-rise areas, where the sediment ridges are thicker, sediment waves are evident in the upper stratigraphic units, while the remaining section is characterized\nby the development of channel-levee complexes (seen as small-scale erosional channels, bordered by depositional reliefs consisting of variable-amplitude reflector packages\nwedging out away from the channels). Channel-levee complexes are locally associated with poorly developed sediment waves. The origin of these features is likely related to\ntransport by turbidity flows from the edge of the Antarctic shelf and implies the presence of a more temperate glacial regime than the one dominating since the Late Miocene.\nThe formation of the sediment waves, both in this more proximal area and on the deep rise, is indicative of the impact of bottom-hugging currents during intervals of the\nCenozoic history of the margin. No constrains are available at present on the nature of these currents nor on the timing of their activity; down-slope turbidity currents,\ndownwelling dense waters or slope parallel contour currents are possible mechanisms. Despite this substantial uncertainty, the observed progressive upward attenuation of the\nwave amplitudes indicates that substantial variations of sediment delivery and dispersal occurred through time. We suggest that the interval of more complex depositional\ngeometry in the proximal areas reflects higher bottom current velocity and/or increased sediment input perhaps during conditions of temperate, wet-based ice sheet on the\ncontinent. These conditions were conducive to high rates of melt-water production, formation of dense plumes, and enhanced sediment input." ; prodottidellaricerca:prodottoDi istituto:CDS080 ; pubblicazioni:autoreCNR unitaDiPersonaleInterno:MATRICOLA20147 . @prefix parolechiave: . prodotto:ID48851 parolechiave:insiemeDiParoleChiave . parolechiave:insiemeDiParoleChiaveDi prodotto:ID48851 .