Study and comparison of host magmatism and controlling factors of Zavarian and Sari_Gunay gold deposits in Sanandaj-Sirjan metamorphic zone and Urmia-Dokhtar magmatic belt
Executor of project: Dr. Seyed Mehran Heidari
Project Associates: Dr. Jalil Ghalamghash - Eng. Tahmine Hasanzadeh
2021
Zavarian epitermal gold (copper) deposit is located in an intracontinental volcanic cone (stratovolcano) of Lower Miocene age, in the middle of the Urmia-Dokhtar magmatic arc. The host rocks of this mineralization include a set of basaltic, andesitic-basaltic, andesitic, dacitic, as well as granodiorite and tonal units that have been exposed in volcanic form (lava and pyroclastic) and semi-deep massifs. These rocks are calc-alkaline in composition and based on the pattern of changes in rare earth elements (LREE, LILE enrichment with respect to HREE, HSFE and negative anomalies of Ti, Nb and low values of Nb / Y ratio) Characteristics of related magmas with subduction environment with crustal contamination. Structural studies point to the key role of right-wing faults (shear zone) as a controller of Miocene sedimentary basins (Qom Formation) and to create the necessary conditions for local tensions and outflow of volcanic activity in this area. The type of hydrothermal alterations and their dispersion with the distribution of mineralized silica veins near and within semi-deep masses and also the type of mineralization sequence with the presence of magnetite, tourmaline and sulfides such as chalcopyrite and pyrite as magmatic fluids they refer to the formation of mineralization. Studies of fluids involved from ore-bearing quartz in this range show a homogenization temperature of 220 to 350 ° C with a salinity of between 10-15% and the weight equivalent of NaCl.
Comparison of this mineralization with Sari-gunay epithermal gold deposit 230 km northwest of Sanandaj-Sirjan zone, although with similarities such as type of mineralization, volcanic host rock, type of mass-related alterations, they refer to the mineralization process. But differences such as type and age of magma, alkalinity, salinity of ore ores, type of associated metal ores, volume of magmatic activity, erosion rate, with the formation of shear zone structure from Lower to Middle Miocene and increasing role of atmospheric fluids and its mixing is associated with magmatic fluids. In other words, the magmatic formation of the Lower and Middle Miocene magmatic phases in these areas is related to the formation of right-sided shear zones and the creation of local tensions in the orogenic phases, especially after collisions.