Neodymium isotopes in seawater samples collected during the IN2017-V01 voyage of the RV Investigator

Samples were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; 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.
Ten litres seawater samples were collected using a CTD rosette equipped with Niskin® bottle and filtered through a 0.45µm Acropak® capsule filter directly into acid-cleaned 10 L polyethylene jerrycans. Samples were then acidified to pH 2 with 2 mL/L of distilled 6M HCl in a laminar flow hood. These samples were analysed for neodymium (Nd) isotopes, a tracer of ocean circulation. 
In the home laboratory (IMAS Trace-Metal Lab, UTAS, Hobart, Australia), seawater samples were pre-concentrated using pre-packed Nobias® PA1L (Hitachi Technologies, Japan) chelating resin cartridges following the method of Pérez-Tribouillier et al., (2019). Rare Earth Elements were separated using anion-exchange chromatography (Anderson et al., 2012) and cation-exchange chromatography (Struve et al., 2016). Finally, Nd isotopes were isolated using LN-Spec column chemistry (Pin and Zalduegui, 1997).
Purified seawater sample Nd concentrations were checked prior to isotopic analysis using Sector Field Inductively Coupled Mass Spectrometry (ICP-MS) at the Central Science Laboratory (UTAS, Hobart, Australia). Nd isotope ratio measurements were then carried out at the Geochemistry Laboratory of the School of Geography, Environment and Earth Sciences of Victoria University of Wellington, New Zealand, using a Thermo Finnigan Triton thermal ionization mass spectrometer (TIMS). Data were reduced offline for outlier rejection and corrected using 146Nd/144Nd = 0.7219 for mass fractionation using the exponential law, and 144Sm/147Sm = 0.20667 for the Sm interference correction on mass 144. JNdi standard data produced for two load sizes using two amplifier configurations were identical: 143Nd/144Nd = 0.512110 ± 24 2sd (46 ppm 2rsd, n = 16) for 1 ng loads using 1013Ω amplifiers, vs. 143Nd/144Nd = 0.512112 ± 3 2sd (6 ppm 2rsd, n = 6) for 100 ng loads using 1011Ω amplifiers. The corrected 143Nd/144Nd were normalised to the JNdi standard with the published value of 0.512115 (Tanaka et al., 2000). Nd isotopic compositions are reported as eNd = [(143Nd/144Nd)sample / (143Nd/144Nd)CHUR - 1]x10,000 , where CHUR is the Chondritic Uniform Reservoir with 143Nd/144Nd)CHUR = 0.512638 (Jacobsen and Wasserburg, 1980).
References
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Tags: CEOS, CONTINENT > ANTARCTICA > WILKES LAND, EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > MARINE GEOCHEMISTRY, EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > OCEAN TRACERS, EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > TRACE ELEMENTS, GEOGRAPHIC REGION > POLAR, ICP-MS > Inductively Coupled Plasma Mass Spectrometer, ISOTOPES, LABORATORY, NEODYMIUM, NISKIN BOTTLES, OCEAN > SOUTHERN OCEAN, RV INVESTIGATOR, SHIPS, TIMS - THERMAL IONISATION MASS SPECTROMETER
Organization: Australian Ocean Data Network