1. Department of Earth Sciences; University of Oxford; South Parks Road Oxford OX1 3AN UK
2. Geological Survey of Canada (GSC); 601 Booth Street Ottawa ON K1A 0E8 Canada
3. Key Laboratory for Continental Dynamics; Institute of Geology; Beijing 100037 China
4. Department of Geosciences; National Taiwan University (NTU); Taipei 10617 Taiwan
5. Institute of Geoscience; University of Mainz; D-55099 Mainz Germany