1. Institute of Geochemistry and Petrology; ETH Zürich; Clausiusstrasse 25 8092 Zurich Switzerland
2. Department of Terrestrial Magnetism; Carnegie Institution of Washington; 5241 Broad Branch Rd. NW Washington D.C. 20015 USA
3. Space Sciences Laboratory; University of California; Berkeley California 94720 USA
4. Institut für Geowissenschaften; Friedrich-Schiller-Universität Jena; Carl-Zeiss-Promenade 10 07745 Jena Germany
5. Institut für Planetologie; Westfälische Wilhelms-Universität Münster; Wilhelm-Klemm-Str. 10 48149 Münster Germany
6. Laboratori Nazionali del Gran Sasso; Ist. Nazionale di Fisica Nucleare Via G. Acitelli 22 I-67100 Assergi (AQ) Italy
7. Department of Physics and Astronomy; Purdue University; West Lafayette Indiana 47907 USA
8. Department of Earth, Atmospheric, and Planetary Sciences; Purdue University; West Lafayette Indiana 47907 USA