3980 13 archive 337 disk0/00/00/39/80 2008-04-07 14:15:58 2008-07-17 22:32:14 2008-07-16 17:03:51 article show Hemer M Post AL O'Brien PE Craven M M.Craven@utas.edu.au Truswell EM Roberts D D.Roberts@utas.edu.au Harris PT pub 040310 260104 770102 restricted Copyright © 2007 Cambridge University Press Publishers version/PDF may be used in an institutional repository or PubMed Central after 12 month embargo category => A1 categoryDesc => Refereed Article in a Scholarly Journal eprintID => 0 field1 => Antarctic Science field10 => field11 => field12 => field13 => field2 => UK field3 => field4 => field5 => DOI:10.1017/S0954102007000697 field6 => Cambridge University Press field7 => 0954-1020 field8 => field9 => funding => T grant => lastUpdate => 18/02/2008 rfcd => 260104 seo => 770102 themeArea => AMS title => Sedimentological signatures of the sub-Amery Ice Shelf circulation tor => SB uid => 50240 update => no Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting. Both cores comprise Holocene siliceous muddy ooze (SMO), however, AM01b also recovered interbedded siliciclastic mud, sand and gravel with inclined bedding in its lower 27 cm. This interval indicates an episode of variable but strong current activity before SMO sedimentation became dominant. 14C ages corrected for old surface ages are consistent with previous dating of marine sediments in Prydz Bay. However, the basal age of AM01b of 28250 230 14C yr BP probably results from greater contamination by recycled organic matter. Lithology, 14C surface ages, absolute diatom abundance, and the diatom assemblage are used as indicators of sediment transport pathways beneath the ice shelf. The transport pathways suggested from these indicators do not correspond to previous models of the basal melt/freeze pattern. This indicates that the overturning baroclinic circulation beneath the Amery Ice Shelf (near-bed inflow–surface outflow) is a more important influence on basal melt/freeze and sediment distributions than the barotropic circulation that produces inflow in the east and outflow in the west of the ice front. Localized topographic (ice draft and bed elevation) variations are likely to play a dominant role in the resulting sub-ice shelf melt and sediment distribution. 2007 published Antarctic Science 19 Cambridge University Press 497-506 10.1017/S0954102007000697 TRUE 0954-1020 http://dx.doi.org/DOI:10.1017/S0954102007000697 5892 4 3980 1 application/pdf en staffonly

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2008-10-01 3980.pdf 532731 http://eprints.utas.edu.au/3980/1/3980.pdf