georefid:2008-039595SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2008-0395952007-01-01publicationgeorefid:2008-039595Lucchi, Renata G.Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, ItalyauthorRebesco, MicheleIstituto Nazionale di Oceanografia e di Geofisica Sperimentale, ItalyauthorGeological Society of London, London, United KingdompublisherdocumentHardcopyIn: Viana, Adriano R. (editor), Rebesco, Michele (editor), Economic and palaeoceanographic significance of contourite deposits276111-127Deep-sea finely laminated and barren glacial sediments occur in the sediment drift field offshore the Pacific margin of the Antarctic Peninsula where a weak contour current flows at present to the SW. Atypical sedimentary facies were related to the coexistence and interaction of different sedimentary processes. Three "end-members" of radiograph facies were defined to represent the sedimentary sequences controlled by a dominant process, as follows. (1) Direct influence of turbidity currents on sedimentation is observed in the area surrounding the Alexander Channel system with silty layers interbedded with laminated mud free of ice-rafted debris (IRD). (2) Distal meltwater turbid flows dominate the more proximal area of the top plateau with structureless and coarser-grained sediments containing IRD. (3) Along the crest of the drift, persistent weak bottom currents control the deposition of fine-grained sediments conveyed into the system through other processes. These laminated sediments contain IRD and are, atypically, not bioturbated, because of unusual, climatically related, environmental conditions of suppressed primary productivity and oxygen-reduced deep waters. These glacial contourites were observed on most of the Antarctic margin with the exception of the areas in which polynyas were maintained during the glacial stages. Glacial contourites can be used as a proxy to define temporal and spatial extension of the Antarctic sea-ice.completedQuaternary geologyAntarctic PeninsulaAntarcticaCenozoicclastic sedimentscontinental margincontour currentscontouritecurrentsdeep-sea sedimentationdriftDrift 7geophysical methodsgeophysical profilesgeophysical surveysglacial environmenticelaminationsLeg 178lithofaciesmarine sedimentationmudocean currentsOcean Drilling ProgramODP Site 1096ODP Site 1097ODP Site 1101paleoclimatologypaleoenvironmentplanar bedding structurespolynyasprogradationQuaternarysea icesedimentary structuressedimentationsedimentsseismic methodsseismic profilessiltSouthern Oceansurveysthicknessturbiditeturbidity currentsurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1096urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1097urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1101urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignEnglishgeoscientificInformation-80.0000-70.0000-70.0000-64.0000