Improvement and performance testing of melting system for measurement of trace elements in firn core drilled at NEEM site, Greenland

ABSTRACT

A melting system was improved for measurement of trace elements in a firn core drilled at the North Greenland Eemian Ice Drilling (NEEM) site (77.45°N, 51.06°W). The melting heads of the melting system were specifically constructed with fluorinated ethylene propylene (FEP)-coated copper (type A) and pure nickel (type B) to reduce percolation of melted samples. Firn core sections with densities in the range of ~0.76–0.86 g cm⁻³ (depth interval: ~58.10–88.83 m) and ~0.56–0.76 g cm⁻³ (depth interval: ~17.32–58.10 m) were successfully decontaminated by the melting system with type A and B melting heads, respectively, as verified by the volume ratios of melted samples from inner and outer zones and video recorded during the melting procedures. Systematic performance tests of the type A melting head melter were performed using artificial ice cores. The procedural blanks and detection limits of V, Cr, Co, Rb, Cd, Ba, Tl, Th and U were generally lower than those in previous studies, whereas the levels of Mn, Sr and Pb were similar to those reported elsewhere. The concentration ratios of these elements from inner and outer zones of the melting head indicated that the melting system had good decontamination efficiency. Finally, the concentrations of elements in the NEEM firn core measured following mechanical removal of the outer layer with chisels and the type A melting head melter showed a good agreement with each other.

KEYWORDS:

• Melting system
• firn core
• performance test
• trace elements
• NEEM

Acknowledgments

We thank all personnel in the field for the sampling work carried out during the 2009 NEEM deep ice core drilling campaign. The NEEM project was directed and organised by the Center for Ice and Climate at the Niels Bohr Institute and the Polar Programs office of the US National Science Foundation. The project was supported by funding agencies and institutions in Belgium (FNRS-CFB and FWO), Canada (NRCan/GSC), China (CAS), Denmark (FIST), France (IPEV, CNRS/INSU, CEA and ANR), Germany (AWI), Iceland (Rannls), Japan (NIPR), Korea (KOPRI), Netherlands (NOW/ALW), Sweden (VR), Switzerland (SNF), the UK (NERC) and the USA (US NSF OPP). This work was supported by a research grant (PE18040) from the Korea Polar Research Institute. The authors wish to thank the anonymous reviewers for providing helpful comments which improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the Korea Polar Research Institute research programme [PE18040];