1. Division of Geosciences and Environmental Engineering, Luleå University of Technology, S-971 87 Luleå, Sweden
2. ALS Laboratory Group, ALS Scandinavia AB, Aurorum 10, S-977 75 Luleå, Sweden
3. Department of Earth Sciences, Durham University, Durham, UK
4. Department of Geosciences, Natural History Museum, Stockholm, Sweden
5. Department of Chemistry, Uppsala University, Uppsala, Sweden