This theme involves modeling isotopic evolution (Rb-Sr, Sm-Nd, U-Th-Pb-He, and K-Ar systems) of the Earth, and specifically, how the various isotopic systems have evolved through time in various terrestrial reservoirs (e.g., lower and upper mantle, lower and upper continental crust, atmosphere) is an interesting research area. The goal is to reconcile geophysical evidences (that support whole mantle convection) with the geochemical signatures (that support layered mantle convection). Approach is to solve numerical models of mass and species transport, and find the most plausible solution that mimics the present-day Earth.