Browsing by Author "Foster, S"

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    Beryllium isotope signatures of ice shelves and sub-ice shelf circulation
    (Elsevier, 2019-01-01) White, DA; Fink, D; Post, AL; Simon, KJ; Galton-Fenzi, BK; Foster, S; Fujioka, T; Jeromson, MR; Blaxell, M; Yokoyama, Y
    Be isotopes are a useful tracer of sediment source and transport pathways but have not been widely tested in glacio-marine environments. We measured Be isotopes in a range of depositional environments from open marine, sub-ice shelf and subglacial settings throughout Prydz Bay, one of Antarctica's largest ice drainage systems. We find that strong sub-ice shelf and bottom current circulations can advect 10Be-rich open marine sediments into an ice shelf cavity, and 10Be-poor terrestrial sediments onto the continental shelf at the ice shelf outflow, meaning that 10Be concentrations reflect sub-ice shelf circulation patterns rather than depositional environment. However, HCl-extractable 10Be/9Be ratios can provide a more robust discrimination of sediment deposited in open marine and sub-ice shelf settings. Thus, Be isotopes are a useful tracer of both environmental setting and sub-ice shelf circulation strength in both modern and paleo-ice sheet margins. Crown Copyright © 2018 Published by Elsevier B.V.