Chemical structure of the Earth’s mantle defined by fast diffusion elements like helium

A theoretical model and numerical simulation(i.e.,Zhu et al.2019)demonstrates that the Earth’s lower mantle was intrinsically stratified for helium(He)by thermal diffusion owing to adiabatic temperature gradient in the Earth.This finding helps to explain the two longstanding problems:the helium concentration paradox and the heathelium paradox.