Seawater Nd isotopes and concentrations from the US-GEOTRACES North Atlantic zonal transect (NAZT), 2010 and 2011 on cruises KN199-04 and KN204-01, analyzed at LDEO (NCEI Accession 0294380)

Acquisition Description:
Methodology: A detailed description can be found in Stichel et al. (2015). See the links below for summaries of the described methodology from the paper.

KN199-04 Methodology (pdf)

KN204-01 Methodology (pdf)

Fig. 1: Sample locations for the Intermediate Data Product.

References: (References listed in the data are codes [1], [2], or [3], corresponding with the following publications/manuscripts)

[1] Stichel, T., Hartman, A.E., Duggan, B., Goldstein, S.L., Scher, H., Pahnke, K., 2015. Separating biogeochemical cycling of neodymium from water mass mixing in the Eastern North Atlantic. Earth Planet. Sci. Lett. 412, 245–260. https://doi.org/10.1016/j.epsl.2014.12.008

[2] Hartman, A., Goldstein, S., Pena Gonzalez, L. D., Duggan, B., Pahnke, K., Scher, H., Stichel, T., in prep. Seawater neodymium composition in the open ocean North Atlantic: water mass signatures and transport.

[3] Duggan, B., Hartman, A.E., Stichel, T., Goldstein, S.L., Pahnke, K., Bizimis, M., Scher, H., in prep. Neodymium Concentrations and Isotopic Signature of the Deep Western Boundary Current Across Line W

Table 1: Summary of the procedures applied in the involved laboratories of University of Hawaii at Mano (UH), Lamont-Doherty Earth Observatory (LDEO) and University of South Carolina (USC).

Step

UH

LDEO

USC

Pre-concentration

Spiked with 146 Nd prior to co-precipitation with FeOOH (~20mg Fe per sample)

Spiked with 150 Nd prior to co-precipitation with FeOOH (~20mg Fe per sample)

Nd and REE extraction with C18 cartridges, not spiked

Chromatographic separation

2-step separation:
1. 1.4ml AG50W-X8 (200-400µm) as primary column. 2. 0.7ml AG50W-X8 (200-400µm) with Alpha-HIBA to purify Nd.
3. ~100µl TRU-Spec column for removal of any remaining Alpha-HIBA in samples.

2-step separation:
1. 100µl RE-Spec (100-150µm) as primary column.
2. 0.7ml AG50W-X8 (200-400µm) with Alpha-HIBA to purify Nd.

1-step separation:
2ml LN-Spec (50-100µm) for Nd purification. No primary column needed because major ions were removed during pre-concentration

Mass spectrometry

VG-Sector TIMS, NdO+, spiked for simultaneous isotope dilution and composition analysis

VG-Sector54 TIMS, NdO+, spiked for simultaneous isotope dilution and composition analysis

Thermo Neptune Plus MC-ICPMS

Other

Concentrations were determined on a previously separated 500ml aliquot by isotope dilution