March 2025 - Chapter book on Earth's mantle rheology
In “Structure and dynamics of the Earth’s interior 2: Composition and structure of the Earth’s mantle”, ISTE Editions
Structure and dynamics of the Earth’s interior 2
Chapter 7
Earth’s mantle rheology (pages : 221-248)
S. Demouchy & P. Cordier
This chapter summarizes the basic agents (point defects, dislocations and grain boundaries) and physical mechanisms of plastic deformation as well as the key observables, which permit to infer the existence of ductile deformation into deep Earth's mantle rocks and minerals. It condenses the results of field studies and petro mineralogical investigations, which allow us to further narrow down the main agents of ductile deformation acting in the lithospheric mantle. The chapter recalls the experimental tools currently used to qualify and quantify ductile deformation. It also provides the best semi-empirical equations describing the ductile deformation of mantle minerals and rocks to date. Finally, the chapter summarizes new advances in computational capabilities, which have led to the establishment of flow laws directly at mantle strain rates, thus without the need to extrapolate laboratory results to slower and Earth-like strain rates, and the identification of deformation mechanisms in lower mantle minerals.