The Earth’s mantle has experienced multiple modifications during its 4.5 billion year history of dynamic evolution. Geochemical depletion occurs mainly in the upper mantle during partial melting events linked to the formation of oceanic and continental crust. Enrichment is mainly associated with recycling of crustal materials to the mantle via subduction and related mantle upwelling. Fluids likely play a key role to trigger these processes. In the last decade, several new geochemical proxies have been developed to study mantle processes, including “non-traditional” stable isotope and radiogenic isotope systems (long- or short-lived) that can now be analyzed with very high precision. With this session we want to invite contributions, which improve our understanding of modern and ancient mantle dynamics, and enable to fingerprint mantle reservoirs that formed during the whole history of the Earth.