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

• Published in: Earth and Planetary Science Letters
• Main Authors: White, Duanne A., Fink, David, Post, Alexandra L., Simon, Krista, Galton-Fenzi, Ben, Foster, Simon, Fujioka, Toshiyuki, Jeromson, Matthew R., Blaxell, Marcello, Yokoyama, Yusuke
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Prydz Bay; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://researchprofiles.canberra.edu.au/en/publications/e9cae090-0e14-4169-9057-b61b7959d3c1; https://doi.org/10.1016/j.epsl.2018.10.004; http://www.scopus.com/inward/record.url?scp=85055582816&partnerID=8YFLogxK; http://www.mendeley.com/research/beryllium-isotope-signatures-ice-shelves-subice-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 10 Be-rich open marine sediments into an ice shelf cavity, and 10 Be-poor terrestrial sediments onto the continental shelf at the ice shelf outflow, meaning that 10 Be concentrations reflect sub-ice shelf circulation patterns rather than depositional environment. However, HCl-extractable 10 Be/ 9 Be 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.