Beryllium isotope signatures of ice shelves and sub-ice shelf circulation

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.

Citation: Duanne A. White, David Fink, Alexandra L. Post, Krista Simon, Ben Galton-Fenzi, Simon Foster, Toshiyuki Fujioka, Matthew R. Jeromson, Marcello Blaxell, Yusuke Yokoyama, Beryllium isotope signatures of ice shelves and sub-ice shelf circulation,
Earth and Planetary Science Letters, Volume 505, 2019, Pages 86-95, ISSN 0012-821X,
https://doi.org/10.1016/j.epsl.2018.10.004