Earth’s lower mantle is the most voluminous layer of our planet, regulating heat and material fluxes from the core to the surface. The chemical and physical properties of the lower mantle play an important role in controlling Earth’s early evolution, differentiation of the mantle and core, fate of subducting slabs and rising plumes, deep rock/volatile cycling, evolution of geochemical reservoirs, etc. However, many key questions in terms of long-term mantle evolution and present day thermochemical structures are still unanswered. Conflicting hypotheses on the nature and origin of lower mantle signals remain difficult to be distinguished from a single discipline. In this session, we invite contributions from geophysical observations and modeling, geodynamic modeling, geochemistry, mineral physics experiments and theory, as well as truly multi-disciplinary approaches to allow for efficient interdisciplinary communications and to provide new insights into the evolution of our planet.