Migration of Elements

Migration of Elements 

the movement and redistribution of chemical elements in the earth’s crust and on its surface. The term was introduced by A. E. Fersman in 1923.

Migration of elements may take place in the liquid phase (in melts, hydrothermal solutions, and subterranean and surface water), in the gaseous phase (with volcanic gases and fumaroles, and gases from mineral sources, petroleum deposits, and decaying organic compounds), and in the solid phase (as a result of diffusion and recrystallization). Migration in solid form takes place mainly on a mechanical basis (for example, taluses and flows of water and dust). In aqueous solutions, elements migrate in the form of ions, molecules, and colloidal particles; in gases they move as molecules and aerosols.

The ability to migrate differs in different elements; it depends on the nature of the chemical compounds and on the physicochemical conditions under which the elements migrate. The out-washing and dispersion of certain chemical elements and the accumulation of others, which often produces commercial deposits, take place as a result of the migration of elements. Intensive migration of elements is observed during the processes of metasomatism and chemical differentiation in marine bodies of water.

Biogeochemical processes play a major role in the migration of elements that takes place under the influence of external processes. Methods of geochemical mineral prospecting are based on the regularities of the migration of elements.

REFERENCES

Vernadskii, V. I. Ocherki geokhimii, 4th ed. Moscow-Leningrad, 1934.
Fersman, A. E. Geokhimiia, vol. 2. [Leningrad] 1934.
Mason, B. Osnovy geokhimii. Moscow, 1970. (Translated from English.)
Shcherbina, V. V. Osnovy geokhimii. Moscow, 1972.

V. V. SHCHERBINA