1. Y. Makovsky, S. L. Klemperer, L. Ratschbacher, Department of Geophysics, Stanford University, CA 94305-2215, USA.
2. L. D. Brown, Department of Geological Sciences, Cornell University, Ithaca, NY 14853, USA.
3. Ming Li, Wenjin Zhao, and Fanle Meng, Chinese Academy of Geological Sciences, Baiwanzhuang Road 26, Beijing 100037, China.