In geology, and more generally, the Planetary differentiation or differentiation is the development of various materials from an originally homogeneous material by segregation. Conditions are the formation of different phases, see phase diagram of which must be a fluid, at least, and a movement drive, usually due to density differences in the gravitational field. The mobile phase can be aqueous, see, eg, hydrothermal solution, molten rock ( magma ) or liquid metal.
The magmatic differentiation has resulted, for example, the emergence of the light continental crust floats on the mantle permanently in contrast to the oceanic crust.
During the formation of planets, there are several processes that lead to melt, causing the heavy, metallic phase collects in the center. In the case of the solar system the various conditions during differentiation and the elapsed time are the methods of radiometric dating available.