Dataset: Dissolved REE concentrations and Nd isotopes reported by OSU researchers from samples collected on the GEOTRACES EPZT R/V Thomas G. Thompson cruise TN303 from November to December 2013

Samples were filtered, acidified, and split at sea. Samples were collected by Niskin bottle and the towed GeoFish. Refer to the EPZT cruise report for more information on cruise operations (http://dmoserv3.whoi.edu/data_docs/GEOTRACES/EPZT/GT13_EPZT_ODFReport_All.pdf). 

We prepared our 5L split for neodymium isotopic analysis following Shabani et al. (1992). Samples were pH-adjusted to pH ~3.5, then pumped through 300 µl of HDEHP in a C18 cartridge to capture REEs. Rare earth elements were eluted from the cartridge using 6M HCl, then Nd was isolated using sequential chromatographic columns: AG50-X8 (BioRad) and Ln-Spec (Eichrom). Neodymium isotopic measurements were made at Lamont-Doherty Earth Observatory (Palisades, NY) using a Thermo Neptune multicollector ICP-MS.

For REE concentrations we removed an aliquot after pH-adjustment of each sample. Sample methodology is described in Behrens et al. (2006), as Lab #3. We preconcentrated 20 ml of sample offline using a SeaFast PICO system (ESI), then analysed the resulting solution at Oregon State University (Corvallis, OR) using a Thermo X-Series II ICP-MS.

Problem Report: Cerium measurements yielded questionable data during a couple of run days, these data are indicated using IODE quality flag 3– Questionable Data. Sample gaps in REE concentrations are due to analytical error during pre-concentration, sample gaps in Nd isotope data are due to insufficient quantity of Nd to make a measurement.