In the preceding chapter, we have seen how the surprising chemical balances at the times of the most intense tectonic plate activities are an indirect evidence of phono-fission reactions. Recent results, observed at the scale of the Earth’s crust and reproduced at the scale of the laboratory, may be extended to the different layers of the planet like the atmosphere and the bulk Earth (mantle and outer core). The mantle of our planet is characterized by very high pressures and temperatures (~150 GPa and ~ 4,000 °C) that can favor this kind of reactions. The most important chemical changes in the Earth’s crust evolution are recognized also at the internal Earth’s layers. Such an internal evolution may be interpreted consistently with and analogously to that of the crust. Summarizing, an overall decrement in iron of 21% is only partially balanced by consistent increments in silicon and magnesium (SI-MA). The remaining unbalanced part of the iron decrement (about 5%) should have contributed (by migration) to the outer core formation, where the iron content is about equal to 80% of the total mass.