Geochemistry of Rare Earth Elements and mineral chemistry of garnet in Darreh Zerreshk skarns (southwest of Yazd)

Garnet is the most abundant calc-silicate mineral in the Darreh Zereshk skarns, and occurs as grained euhedral, to massive anhedral, isotropic to anisotropic crystals and display concentric and sector zoning or no zoning. Based on mineralogical investigations and paragenetic relations, garnet formed during progrademetasomatic stage of skarn formation. Geochemically they display two different patterns, i.e: (1) LREE-enriched and HREE-depleted, with strong positive Eu anomaly and (2) HREE-enriched and LREE-depleted with small Eu anomalies characteristic of andraditic and grassuleritic garnets, respectively. Electron probe micro analyzer (EPMA) identifies the garnets from Darreh Zerreshk skarn as grossular–andradite (grandite) solid solution series, with a less contents of spessartine and pyrope components. This is significant of a composition similar to Cu, Fe and Au skarn.