georefid:2003-022406georefid:2003-022395SEDIS Publication Catalogue

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http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.178.212.20012002-01-01publicationgeorefid:2003-022406doi:10.2973/odp.proc.sr.178.212.2001Hassler, Lauren E.Appalachian State University, Department of Geology, Boone, NC, United StatesauthorCowan, Ellen A.Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, ItalyauthorTexas A&M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentDigitalIn: Baker, Peter F. (editor), Camerlenghi, Angelo (editor), Acton, Gary D. (editor), Brachfeld, Stefanie A., Cowan, Ellen A., Daniels, James, Domack, Eugene W., Escutia, Carlota, Evans, Andrew J., Eyles, Nicholas, Guyodo, Yohan J. B., Hatfield, Kate L., Iorio, Marina, Iwai, Masao, Kyte, Frank T., Lauer, Christine, Maldonado, Andres, Moerz, Tobias, Osterman, Lisa E., Pudsey, Carol J., Schuffert, Jeffrey D., Sjunneskog, Charlotte M., Weinheimer, Amy L., Williams, Trevor, Winter, Diane M., Wolf-Welling, Thomas C. W., Ramsay, Anthony T. S. (editor), Proceedings of the Ocean Drilling Program, scientific results, Antarctic glacial history and sea-level change; covering Leg 178 of the cruises of the drilling vessel JOIDES Resolution; Punta Arenas, Chile, to Cape Town, South Africa; sites 1095-1103; 5 February-9 April 1998178Pebbles (>10 mm) sampled from three drill sites on the continental rise west of the Antarctic Peninsula during Ocean Drilling Program Leg 178 were classified by shape and roundness. In addition, pebble lithology and surface texture were visually identified. To increase the pebble sample number to 331, three sites that were drilled 94 to 213 km from the continental shelf edge were integrated into the data set using magnetostratigraphy for core correlation. Pebbles were compared in three groups defined by the same stratigraphic intervals at each site: 3.1-2.2 Ma (late Pliocene), 2.2-0.76 Ma (late Pliocene-late Pleistocene), and 0.76 Ma to the Holocene. Pebble lithologies originate from sources on the Antarctic Peninsula margin. Most pebbles are metamorphic and sedimentary pebbles are rare (>6%), whereas mafic volcanic and intrusive igneous lithologies increase in abundance upsection. Pebbles from 3.1 to 0.76 Ma, plotted on sphericity-roundness diagrams, indicate original transport as basal and supraglacial/englacial debris. Pebbles are abundant and of diverse lithology. From 0.76 Ma to the present, the number of pebbles is low and their shape characteristics indicate they originated as basal debris. Observed changes in ice-rafted pebbles can be explained by growth of an ice sheet and inundation of the Antarctic Peninsula topography by ice approximately 0.76 Ma. Prior to this, outlet and valley glaciers transported debris at high levels within and at the base of the ice. The mass accumulation rate of sand fluctuates and includes rounded quartz grains. Ice-sheet growth may have been accompanied by overall cooling from subpolar to polar glacial regimes, which halted meltwater production and enhanced the growth of ice shelves, which consequently reduced sediment supply to icebergs.completedStratigraphyAntarctic OceanAntarctic PeninsulaAntarcticaCenozoicclastic sedimentsclimate changecontinental risecoresdriftglacial geologygrain sizeHoloceneiceice raftingicebergsLeg 178lithofacieslithostratigraphymagnetostratigraphymarine sedimentsNeogeneOcean Drilling Programocean floorsODP Site 1095ODP Site 1096ODP Site 1101paleo-oceanographypaleoclimatologypebblesPleistocenePlioceneQuaternarysea icesedimentsTertiaryupper Plioceneurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1095urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1096urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignurn:org.iodp:exp:178:site:1101urnlargerWorkCitationstudyurn:org.iodp:exp:178urnlargerWorkCitationcampaignEnglishgeoscientificInformation-78.2916-70.1540-67.3401-64.2220Available only on CD-ROM in PDF format and on the Web in PDF or HTML; access date Feb. 24, 2002application/pdfunknownSEDIS Publication Catalogue

ana.macario@awi.de

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