1. School of Geosciences China University of Petroleum (East China) Qingdao Shandong 266580 China
2. Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Mineral Shandong University of Science and Technology Qingdao Shandong 266590 China
3. Department of Earth and Planetary Sciences Yale University New Haven CT 06511 USA
4. PetroChina Exploration and Development Institute Beijing 100083 China
5. Bohai Oil Research Institute Tianjin Branch of CNOOC Ltd, 300459 Tianjin 300459 China