1. Center for Lunar and Planetary Sciences; Institute of Geochemistry; Chinese Academy of Sciences; Guiyang 550081 China
2. University of Chinese Academy of Sciences; Beijing 10049 China
3. Physics Institute; University of Bern; CH-3012 Bern Switzerland
4. State Key Laboratory of Environmental Geochemistry; Institute of Geochemistry; Chinese Academy of Sciences; Guiyang 550081 China
5. Division of Mines and Geology; Sixth Geological Brigade; Hami 839000 China