AN OUTLINE OF METASOMATIC PROCESSES (PART 1 OF 3)

The present outline presents the physical chemistry of metasomatism in a form understood readily by the largest possible segment of the geological profession, in the first instance; this section is concerned especially with the theory of metasornatic zones. Next we discuss the fundamental problems in metasomatism, their relationships to postmagmatic processes and - in particular - to the acid-base relationships in the solutions segregated from the intruded magmatic pool. The body of the paper, however, is concerned with a survey of the several stages of the metasomatic process consequent upon the stages of magmatic evolution; special emphasis is placed upon contact-metamorphic processes, leaching processes (the origin of secondary quartzites, greisen zones, ore enrichment in the contact-metamorphic zone). All the relationships are considered from the standpoint of metasomatic zone distribution. [Metasomatic zonation is shown to be a consequence of the fact that aqueous systems become increasingly acid (th...