Document Type : علمی -پژوهشی
Authors
1
M.s student in RIES,GSI,Tehran
2
Assistant Professor
3
Associated professor
4
assistant professor in mianeh azad university
Abstract
XVI-B anomaly iron ore deposit is located in Iran-Central structural zone in Bafq area. Based on geological knowledge the oldest rocks in this area are Precambrian metamorphosed units like genaiss, mica-schist, amphibolite and migmatite that formed bedrocks for this mineralization anomaly. The mineralization area is completely covered by a series of Tertiary and Quaternary sediments of Bafq Basin. Mineralization intrusion mass units are specified by alkaline diorites-syenites. This deposit contains a variety of igneous, metamorphic and metasomatic rocks. Based on the petrographic view, igneous rocks are granitoid that are include: gabbro, syenite, quartz monzonite, granite, and highly altered basaltic rocks (metabasite). The metamorphic rocks are marble, epidote actinolite, actinolite (metasomatic rocks) and skarn rocks. Metallic mineralization has occurred in relation to syenite, gabbro and skarn rocks. Magnetite is the most abundant iron oxide ore in this anomaly and it can be seen with aggregate, ribbon, fill in the void and spray texture and its pieces are shaped to be amorphous. Magnetite is oxidized near the surface and is altered to hematite, goethite, and other iron oxides. Other metallic minerals participants with magnetite are pyrite and chalcopyrite that can be seen with quartz, actinolite, calcite, and epidote in various forms within host rocks, syenite intrusions, gabbros, and skarns. Accordance with rare element diagrams in iron mineralization and intrusive masses, which indicates the origin of mineralization is similar to intrusive masses probability. Iron oxide grade varies between 5 and 75 percent in the ore. The iron element has a negative correlation with titanium, magnesium, manganese, phosphorus, potassium and sodium oxides. Based on cobalt to nickel, chromium to nickel, chromium to vanadium relationship, this iron deposit is placed in the hydrothermal deposits range. Due to the Al / Co and Sn / Ga ratios, this deposit is located within the skarn type deposits. Based on the scattering patterns of trace elements XVI-B anomaly iron ore is more similar to the skarn type deposits. Geological, mineralogical and geochemical evidence of magnetite indicates skarn origin for iron mineralization of XVI-B anomaly. This means that iron is displaced by hot fluids from the intrusive masses and accumulates in the interval between the metamorphic units and marble.
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