ABSTRACT

The distribution of chemical elements in the Earth's crust and its inferred interior is controlled mainly by the density periodicity of the elements, and is further perturbed by chemical affinity of the elements. The chemical elements have been classified into four major groups: heavy, medial, light and volatile, according to the physical and chemical properties and the distribution pattern of the elements. The light elements are generally enriched in the Earth's surface and the heavy elements are concentrated in its center. The abundances of most of the heavy and light elements increase and decrease respectively, very rapidly with increasing depth, whereas those for the medial and volatile elements remain relatively uniform throughout the Earth (except the core). Chemical affinity controls the abundances of the volatile and medial elements more than those of the light and heavy elements. On the basis of the principles of elemental distribution observed in the Earth, it is deduced that the chondrites were formed in an enviornment which experienced little gravitational influence, whereas the achondrites were formed under the influence of gravitation. The distribution of chemical elements in the Sun does not appear to be influenced by its gravitational field, which might be a consequence of nuclear fusion processes.