基金We wish to thank Pinf Luo Zhaohua for his good suggestions and criticism to improve our paper, to thank Prof Y.M. Pan and Q.L. Xie for their support in experimental analyses in the trace elements and REEs, and also to thank Shao Hongxiang and Yang Bin for their assistance in analyses of major compositions at Peking University. The National Natural Science Foundation of. China （Grant No.40420120135 and 40472096） are thankefl for the fthancial support.
基金We wish to thank Zhao Fengshan, Gu Libing and Yang Bin for their assistance with petrochemical analyses at the Key Laboratory of 0rogenic Belts and Crustal Evolution, Peking University, and Chu Zhuyin for his experimental assistance with Sm-Nd isotopic analyses at the Institute of Geology and Geophysics, Chinese Academy of Sciences. This study is financially supported by the National Natural Science Foundation of China （Grant Nos. 40412012035, 40511140503, 40472096, 40502009 and 40472118）.