Nd isotope fractionation on ferrihydrite

Full description

Sheet contains stable 146Nd/144Nd, 148Nd/144Nd, and radiogenic 143Nd/144Nd isotope compositions of conducted adsorption experiments and seawater samples. Details on the locality and field measurements of seawater samples are also given.

The adsorption experiments consist of two batches of experiments that were intended to investigate the isotope fractionation of Nd on ferrihydrite: (1) a time series experiments to monitor kinetic isotope effects and (2) experiments in isotopic equilibrium with variable amont of sorbed Nd to contrain an isotope fractionation factor. The experiments were carried out in in vented fume cupboard in a clean laboratory at James Cook University. Ferrihydrite was synthesized after Cornell and Schwertmann (2003). Neodymium isotope ratios were measured using the double-spike method after McCoy-West (2020). Neodymium concentrations were measured unsing a Thermo Fisher Scientific iCap TQ-ICP-MS at the Advanced Analytical Centre at James Cook University. Aliquots containing 100 ng Nd were spiked using a 145Nd-150Nd double spike. Neodymium was purified using an ion exchange chromatography protocol after McCoy-West (2020). Isotope ratios of adsorption experiments were measured uisng a Thermo Fisher Scientific Neptune at the Advanced Analytical Centre at James Cook University. The double spike deconvolution was carried out using an in-house Mathematica script.

Seawater samples were collected from Seaham pier (England) in August 2017. The samples were filtered through 0.2 μm cellulose-acetate filters. The Nd isotope ratios of seawater samples were analysed uinsg a Thermo Fisher Scientific TritonPlus thermal ionisation mass spectrometer at Durham University.

References:

Cornell, R.M., Schwertmann, U., 2003. The iron oxides: structure, properties, reactions, occurrences and uses, 2nd ed. Wiley-VCH, Weinheim.

McCoy-West, A.J., Millet, M.-A., Nowell, G.M., Nebel, O., Burton, K.W., 2020b. Simultaneous measurement of neodymium stable and radiogenic isotopes from a single aliquot using a double spike. Journal of Analytical Atomic Spectrometry 35(2), 388-402. doi.org/10.1039/c9ja00308h.