| Summary: | Progress Code: completed Statement: At least 2 standards (typically one in-house standard and the certified standard IAEA-385, International Atomic Energy Agency, Austria) and a blank were included in every digestion batch, which typically involved 24 samples. Purpose These data were collected to determine radioactive isotopes concentrations in the sediment, and to determine vertical particle fluxes for palaeoceanographic reconstructions. Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator, during the IN2017_V01 voyage from January 14th to March 5th 2017 (Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC) and a Kasten corer (KC). The MC were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The KC was sub-sampled using a u-channel; and sliced every centimetre once back the home laboratory (IMAS, UTAS, Hobart, Australia). About 200 mg of dried and ground sediment were weighed into a clean Teflon vial and oxidized with a mixture of concentrated HNO3 and 30% H2O2 (1:1). The resulting solutions were gravimetrically spiked with ~ 24 pg of 229Th (NIST 4328C, National Institute of Standards and Technology, USA) and ~ 2 ng of 236U (IRMM-3660a, Institute for Reference Materials and Measurements, European Union) and left to equilibrate overnight. Samples were then digested in open vials using an acid mixture comprising 10 mL HNO3, 4 mL HCl, and 2 mL HF, at 180°C until close to dryness. Digested residues were converted to nitric form before being oxidised with a mixture of 1 mL HNO3 and 1 mL HClO4 at 220°C until fully desiccated. Samples were finally re-dissolved in 4 mL 7.5 M HNO3. Thorium and uranium were isolated from the sediment digest using AG1-X8 anion exchange resin (Bio-Rad, USA), following ...
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