1. Qingdao Institute of Marine Geology, China Geological Survey, Qingdao 266071, China, China University of Geosciences, School of Earth Resources, Wuhan 430074, China, and Qingdao National Laboratory for Marine Science and Technology, Pilot Laboratory for Marine Mineral Resources, Qingdao 266071, China.(corresponding author).
2. China University of Geosciences, School of Earth Resources, Wuhan 430074, China..
3. Qingdao Institute of Marine Geology, China Geological Survey, Qingdao 266071, China and Qingdao National Laboratory for Marine Science and Technology, Pilot Laboratory for Marine Mineral Resources, Qingdao 266071, China..
4. Tianjin Branch of China National Offshore Oil Corporation Ltd, Tianjin 300452, China..
5. The University of Texas at Austin, Bureau of Economic Geology, Jackson School of Geosciences, Austin, Texas 78712, USA..