Geochemical classification of the elements

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The geochemical and cosmochemical behavior of the elements is controlled by many factors, including size (ionic radius), bonding characteristics, volatility, redox behavior and complexing behavior. Accordingly, the elements may be classified in a number of ways that are useful in geochemical investigations. The most significant of these classification schemes is that developed by V.M. Goldschmidt (1923, 1954) based on the affinity of elements to form various types of compounds. Subsequently, other classification schemes have been developed to account for certain cosmochemical distributions (volatility), abundance distributions in igneous rocks and size/charge relationships.

It is, of course, also common to adopt standard chemical terminology in discussion of the distribution of the elements in rocks and minerals. Thus, the alkali (group IA, excluding H), alkaline earth (group IIA), transition elements (groups IB–VIIB, VIII), rare earth el ...