1. College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, P.R. China
2. Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology, Qingdao 266071, P.R. China
3. Research Institute of Petroleum Exploration and Development, Shengli Oil Company, Sinopec, Dongying 257001, P.R. China
4. College of Resources and Environment, Yangtze University, Wuhan 430100, P.R. China