Recently,the Lin Jian team of the South China Sea Institute of Oceanography,Chinese Academy of Sciences,together with Zhu Rixiang,an academician of the CAS Member and a researcher of the Institute of Geology and Geophysics,made progress in the research of marine lithosphere hydration,quantitatively calculated the distribution of global ocean plate hydration rate,and revealed that the subduction zone is the key place for ocean plate,especially mantle hydration.The relevant research results are published in the National Science Review.
Water has a significant impact on the physical and chemical processes on the surface and interior of the Earth.Seawater enters the lithosphere through cracks and faults on the seabed,causing the hydration of oceanic plates(Figure 1).During this process,seawater causes a decrease in the strength of the lithosphere and alters mantle properties.In addition,water can also affect seismic activity by changing the pressure and friction of rocks,while reducing the melting temperature and viscosity of mantle material,thereby promoting the generation of magma and volcanic activity.Subsequently,the seawater entering the depths of the Earth will be stored inside the Earth,while another portion will be released back into the ocean and atmosphere by volcanic activity.Therefore,the hydration process of ocean plates can affect plate tectonics,mantle convection,and the circulation of material and energy in multiple layers of the Earth.
The latest research indicates that seawater enters the marine lithosphere in a multi episodic manner through mid ocean ridge transform faults and subduction zones(Figure 1).The study quantitatively estimated the distribution of global oceanic lithospheric water inflow rate by statistically analyzing and calculating key parameters of global oceanic plate hydration(Figure 2).According to calculations,the contribution rate of water inflow to the global mid ocean ridge transform fault is approximately 31.2%(~7.08×108 Tg/Myr);The contribution rate of water ingress in the subduction zone is approximately 68.8%(~15.95%)×108 Tg/Myr).Among them,the mantle water inflow rate is mainly contributed by the subduction zone.The above achievements can provide important references for global sea level changes,earthquakes and volcanic activities,fluid solid interactions,and so on.
The research work was supported by the National Key R&D Program,the National Natural Science Foundation of China and the Chinese Academy of Sciences.
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Figure 1.Schematic diagram of marine lithosphere hydration.The first hydration occurred in the mid ocean ridge transition fault system,and the second hydration occurred in the subduction zone
Figure 2.Global distribution of multi episode water inflow in the marine lithosphere
