Geochemical constraints on the origin of the Sterling Hill and Franklin zinc deposits, and the furnace magnetite bed, northwestern New Jersey

The purpose of this chapter is to review two aspects of the geochemistry of the Sterling Hill and Franklin zinc-ironmanganese deposits and the Furnace magnetite bed that underlies the Franklin deposit. These are (1) oxidation and sulfidation states determined from heterogeneous phase equilibria, and (2) stable isotopic compositions determined from analyses of carbonate, silicate, oxide, and sulfide minerals. The data place constraints on the genesis of the ores, which is the topic of the final section of the chapter. This review draws heavily from the results of my own dissertation research on Sterling Hill (Johnson, 1990; Johnson et al., 1990a) and from recent and continuing projects (Johnson et al., 1990b, Johnson, 1994, 1996, 1997; Volkert et al., 2000); it also includes the sulfur isotope results obtained by Ault (1957). For a complete review of the geology of the deposits, the reader is referred to the chapter by Metsger (2001), and to Metsger et al. (1958) and Frondel and Baum (1974). A complete catalog of the extensive literature on the deposits is given by Dunn (1995).