Exploration models for skarn deposits

Most large skarn deposits are zoned in both space and time relative to associated intrusions, and this zonation can be used to guide exploration. Zonation occurs on scales from km to, and reflects infiltrative fluid flow, wallrock reaction, temperature variations, and fluid mixing. In most skarn systems, there is a general zonation pattern of proximal garnet, distal pyroxene, and vesuvianite (or a pyroxenoid such as wollastonite, bustamite, or rhodonite) at the marble front. In addition, individual skarn minerals may display systematic color or compositional variations within the larger zonation pattern. Such patterns are reviewed for several well-studied examples of Cu, W, Au, and Zn-Pb-Ag skarns. In addition, many deposits have endoskarn or other alteration of the associated intrusion and recrystallization or other subtle changes in the surrounding wallrocks.