Redox geodynamics in Earth’s interior

Redox state is an important parameter in describing the thermodynamic state of the Earth’s interior.In contrast to the considerable efforts in early studies that have been expended on the redox state of Earth’s different spheres,much attention in the recent about 10 years has been paid to the effects of redox state on the various geodynamical aspects of Earth’s interior,or more commonly the redox geodynamics.Redox geodynamics plays a critical role in driving many processes that are involved in the accretion,differentiation,and re-shaping of the Earth from its early birth to modern periods and from its surface to the deep interior,including the structure,composition,nature,and evolution of the Earth and the significant effects on many important issues such as the climate change and habitability of the planet.This field has blossomed in these years around the chemical and physical properties of the Earth.In this review,a brief summary is provided for the basic concepts,general background and applications relevant to redox geodynamics.The redox state of the crust and mantle and its evolution have received particular attention in the past years,however,there are still fundamental issues remaining ambiguous,poorly quantified and/or even controversial.At the same time,significant progress has been made,mostly through experimental studies,on the redox geodynamics of the Earth’s interior,including(but are not limited to)the early oxidation of the shallow mantle,the rapid growth of the early continental crust,the redox freezing and melting associated with carbon or hydrogen,the transfer of metal elements and formation of ore deposits,the low seismic velocity and high attenuation of the asthenosphere,the aerobic processes around the core-mantle boundary,and the magma degassing and released gases.Redox geodynamics is becoming increasingly important in renewing the understanding of the chemical evolution,physical properties,and dynamical processes of the Earth.