This work was supported by Natural Science Funds for Distinguished Young Scholars (Grant 21425728), National Key Research and Development Program of China (Grant 2016YFA0203002), the 111 Project (Grant B17019), Self- Determined Research Funds of CCNU from the Colleges' Basic Research and Operation of MOE (Grant CCNU14Z01001 and CCNU16A02029), Excellent Doctorial Dissertation Cultivation Grant from Central China Normal University (2015YBZD024 and 2016YBZZ031), and the CAS Interdisciplinary Innovation Team of the Chinese Academy of Sciences. We gratefully acknowledge the help of Yue'e Peng and Menglan Zhang in China University of Geosciences, Wuhan for their mass spectrometer analysis.