Multidisciplinary investigations of mid-ocean ridges over the last decades reveal that accretion of oceanic crust results from the complex interplay of magmatic and tectonic processes and that fluid circulation within the crust has a major role in hydrothermal activity and deformation processes. However, many aspects concerning fluid-rock interaction, hydrothermal circulation, melt migration and cooling, melt distribution and mantle outcropping at ultra-slow ridges, magmatic or amagmatic extension, evolution of oceanic core complexes, and formation of fault zones, are still debated This session aims to bring together scientists from various disciplines (geophysics, geochemistry, mineralogy, structural geology, numerical modeling) interested in these different themes and in the formation and evolution of the oceanic crust along ridges, and the interactions between magmatic, tectonic and hydrothermal processes.