georefid:2003-068261SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2003-068261<gco:CharacterString>Millennial and sub-millennial-scale variability in sediment colour from the Barra Fan, NW Scotland; implications for British ice sheet dynamics</gco:CharacterString>2002-01-01publicationgeorefid:2003-068261Wilson, Lindsay J.University of Saint Andrews, School of Geography and Geosciences, Saint Andrews, United KingdomauthorAustin, William E. N.authorGeological Society of London, London, United KingdompublisherdocumentHardcopyIn: Dowdeswell, Julian A. (editor), O Cofaigh, Colm (editor), Glacier-influenced sedimentation on high-latitude continental margins203349-365Sediment colour, together with other proxy data, provides a novel, rapid and non-destructive tool in the investigation of glacier-influenced sedimentation on the Barra Fan, NW Scotland. Lightness (L (super *) ) and reflectance (400-700 nm) measurements at this site provide a quantitative estimate of changes in calcium carbonate and clay content. Interstadials are carbonate-rich/clay-poor (higher L (super *) and reflectivity), whereas stadials are carbonate-poor/clay-rich (lower L (super *) and reflectivity). Detailed sedimentological investigations suggest that the last British Ice Sheet (BIS) extended to the outer continental shelf-break shortly after 30 ka BP. This climatic response of the BIS to global cooling at the Marine Isotope Stage (MIS) 3-2 transition marks a significant increase in sediment delivery to the Barra Fan. Prior to 30 ka BP, strong Dansgaard/Oeschger (D/O) cyclicity dominates the record. After 30 ka BP, shorter periodicities prevailed as the BIS reached its maximum extent. Glacier dynamics plays a significant role in the delivery of ice-rafted debris (IRD) across this margin, highlighting the inherent difficulties of correlating millennial-scale IRD events when the IRD is derived from different ice sheets. An event stratigraphy based upon carbonate-rich interstadials provides a more robust means of amphi-Atlantic correlation during this interval.completedQuaternary geologySedimentary petrologyabsolute ageAtlantic Oceanatomic absorptionBarra FanC-14carbonCenozoicchemical compositionchronostratigraphyclastic sedimentsclaycolorcontinental shelfcoresdatesForaminiferaglacial environmentglacial geologyglacial sedimentationglaciersglaciomarine environmentglaciomarine sedimentationgrain sizeHoloceneice sheetsInvertebrataisotopeslithostratigraphymagnetic susceptibilitymarine environmentmarine sedimentationmicrofossilsmineral compositionNorth AtlanticNortheast AtlanticOcean Drilling Programouter shelfpaleomagnetismProtistaQuaternaryradioactive isotopesreflectanceRockall Troughseasonal variationssediment transportsedimentationsedimentssequence stratigraphyspectraspectroscopystratigraphic unitstaxonomyEnglishgeoscientificInformation-11.0000-9.000056.300057.3000