Unravelling the behaviour of the deforming lithosphere in geological settings relies on the reconstruction of pressure-temperature-deformation paths from the preserved metamorphic mineral assemblages. However, polyphase metamorphism and deformation can greatly influence the extent of mineral re-equilibration and the preservation of disequilibrium assemblages, with major implications for the reconstruction of metamorphic paths and for the mechanical behaviour of rocks. This session aims to deepen our understanding of how the preservation of metamorphic minerals and the scale of chemical equilibrium may change with strain, chemical differences and fluid availability. We welcome a wide range of contributions that combine petrology, mineral composition, thermodynamic modelling, trace elements and isotope geochemistry with deformation from the micro- to the orogen-scale. Part of the session will be dedicated (but not limited) to studies that investigate the effects of growth and preservation of metamorphic minerals on the rock rheology in a variety of tectonic settings.