1. State Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing, China
2. College of Geosciences, China University of Petroleum, Beijing, China
3. Institute of Geology and Geophysics, Chinese Academy of Science. 100029, Beijing, China
4. Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
5. Department of Earth Science, University of California, Santa Barbara, CA, USA