1. Institute of Geological Sciences; University of Bern; Baltzerstrasse 1+3 Bern 3012 Switzerland
2. Department of Geological Sciences; Stockholm University; Svante Arrheniusväg 8 Stockholm 106 91 Sweden
3. Institut für Mineralogie; University of Münster; Corrensstraße 24 Münster 48149 Germany
4. Department of Geosciences; University of Oslo; Oslo Norway
5. Steinmann Institut; University of Bonn; Poppelsdorfer Schloss Bonn 53115 Germany