1. Department of Earth and Planetary Sciences, University of California, Riverside, California92521, USA
2. Department of Geology, University of Johannesburg, Auckland Park, South Africa
3. UMR 7285 CNRS IC2MP, University of Poitiers, Poitiers, France
4. Department of Geosciences and Geography, University of Helsinki, Helsinki 00014, Finland
5. Department of Geosciences, The Pennsylvania State University, University Park, Pennsylvania 16827, USA
6. Department of Geosciences, University of Tübingen, 72074 Tübingen, Germany
7. Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut 06511, USA