Volcanic-Associated Massive Sulfide (VMS) Deposits

Massive Cu-Zn-Pb sulfide deposits in predominantly volcanic terranes have been variously termed as ‘volcanic-associated’, ‘volcanic-hosted’, and ‘volcanogenic’. The term ‘volcanic-hosted’ is not entirely appropriate, because the deposits included in this class are not consistently hosted by volcanic rocks, nor do the deposits necessarily form as an integral part of the volcanic process as the term ‘volcanogenic’ implies. The term ‘volcanic-associated’ is considered more appropriate as it accommodates not only the deposits enclosed entirely within volcanic strata, but also those, such as the Besshi deposits (Japan), hosted by sedimentary rocks formed in a dominantly volcanic regime. The most important requirements of the volcanic-associated class of deposits are that penecontemporaneous volcanism must have accompanied the formation of the deposits, and that volcanic rocks must comprise an essential part of the immediate stratigraphic sequence (Franklin et al., 1981).