Mechano-chemical feedbacks during deformation and hydration of peridotites

Abstract

The hydration of the Earth’s mantle is a crucial process for many aspects of our planet, from the behaviour of the tectonic plates to the global water cycle and the origin of life. This process is called serpentinization and has a considerable impact on the rock’s behaviour when under stress. It makes rocks easier to break and is associated with a volume increase that can locally perturb tectonic stress and break surrounding rocks. The rock composing the mantle, peridotite, has however a very low permeability, and water has difficulties to circulate within it. Faulting is thus intimately linked to the water supply during serpentinization. Even though the link between faulting and serpentinization has been established, the way these two processes interact is not fully understood. Tectonically and seismically active zones in oceanic context are recognized to be preferred zones of serpentinization, but most common models for serpentinization do not reflect this major role of tectonics. This work highlights the role of tectonics in serpentinization initiation and maintenance through a combination of microstructural and seismic studies.