基金Acknowledgements This work was supported by China Geological Survey (Grant No. H45C004002, 1212010784007) and the Project of the National Natural Science Foundation of China (Grant No. 40272012).
基金This work was supported by China Geological Survey (Grant No. H45C004002, 1212010784007, ZKD-94-17) and the Project of the National Natural Science Foundation of China (Grant No. 40272012).