Mineralography, geochemistry and Sulfur isotope study in 16B magnetite mineralization anomaly, Bafgh, Yazd

Anomaly XVI-B located in Central Iran Structural Zone. The oldest rock formations in this study area are related to metamorphic rocks which are included gneiss, micaschist, amphibolite and megmatite. Mineralized intruded mass distinguished by alkaline diorite-syenite that cut Bonoshorow metamorphic complex and limestone units. Metallic mineralization is occurred in syenite, gabbro and skarn rocks. Magnetite is the most abundant mineral in anomaly XVI-B and also it has been seen as stripe, mass, disseminated and filling empty space textures. The magnetite grains are shaped to shapeless. Magnetite is oxidized near the surface and converts to hematite, goethite and other iron oxides. Another metallic mineral which are associated with magnetite are pyrite, and chalcopyrite, which have been found in quartz, actinolite, calcite, and epidotite that come with various forms within host rocks, syenite, gabbro, and skarn. According to the graphs of rare earth elements in iron mineralization and intruded units indicates the possible similarity of the source of iron mineralization with intruded mass. The grade of iron oxide in ore deposit varies between 25 and 75 percent. The iron element has a negative correlation with oxide of titanium oxides, magnesium, manganese, phosphorus, potassium and sodium. Based on cobalt relationship with nickel, chromium - nickel, and chromium - vanadium, so anomaly XVI-B iron deposit is related to the hydrothermal deposits. Due to the ratio of Al / Co and Sn / Ga, anomaly XVI-B is recognized as a skarn type deposit. Based on the scattering patterns of the rare elements, anomaly XVI-B is more similar to the skarn type deposit. Geological and mineralogical evidence, as well as the geochemical properties of the magnetite, indicate that skarn deposit is source of iron mineralization. Iron is transported by the hot fluids that come from intruded units that accumulates between boundary of metamorphic and marble units. δ34S value is between 21.24% - 22.27%. The source of Sulphur isotope is meteoric and ancient marine water. As a result, the accompaniment of magnetite with pyrite can be found that the source of magnetite is identical with pyrite.