The migration of heated and compressed chemical elements and compounds such as silicon, aluminium, and general alkali metals through the means of subduction and volcanism is known in the geological world as geochemical cycles.
The geochemical cycle encompasses the natural separation and concentration of elements and heat-assisted recombination processes.
However, a biogeochemical cycle refers to the chemical interactions in surface reservoirs such as the atmosphere, hydrosphere, lithosphere, and biosphere[citation needed] whereas a geochemical cycle refers to the chemical interactions that exist in crustal and sub crustal reservoirs such as the deep earth and lithosphere.
[citation needed] The Earth, as a system, is open to radiation from the sun and space, but is practically closed with regard to matter.
Volcanism is the process that takes place at divergent boundaries by which one tectonic plate separates from another creating a rift in which molten rock (magma) erupts onto the surface of the Earth.