محمد صالحی تینونی

The Takht-e-Gonbad copper mineralization is located about 63 km of northeast of Sirjan city. Hypogene mineralization occurred as stockwork vein-veinlets and thick quartz veins hosted by Oligo-Miocene micro-granodiorite body and Eocene pyroclastic materials (mainly tuff with intermediate composition). The stockwork vein-veinlets contain three generations of mineralization, (1) quartz + magnetite ± chalcopyrite, (2) quartz + chalcopyrite + pyrite + magnetite, and (3) quartz + pyrite + chalcopyrite. Phyllic alteration was mainly developed in the wall rocks around the stockwork quartz vein-veinlets. The supergene mineralization in this deposit is characterized by the replacement of ferrous sulfides by hematite and goethite. Also, formation of the malachite, azurite, and native copper during destruction of the hypogene iron and copper sulfides occurred under oxidizing conditions. The study of the fluids inclusion in quartz crystals of the stockwork vein-veinlets showed that they are chiefly of L+V+S, L+V and V+L types having temperature and salinity ranges of 140-450°C and 0.35-57.8 wt% NaCl eq., respectively. The solid phases are halite, sylvite, and opaque minerals. The studied fluids inclusion in the thick quartz veins are of L+V type having temperature and salinity within the range of  207-344°C and 0.35-3.39 wt% NaCl eq., respectively. Based on microthermometric data, the boiling of the magmatic fluids was the effective factor of the ore and gangue minerals deposition in the stockwork vein-veinlets. Also, cooling and mixing of the atmospheric fluids with magmatic ones account for the deposition of the minerals in the thick quartz veins.  In general, the obtained data in this research revealed that the development and evolution trend of the hydrothermal system in the Takht-e-Gonbad is mostly similar to that of the porphyry copper system.

The Bolboli2 copper ore deposit is located about 110 km southwest of Kerman and lies in the Dehaj-Sarduieh metallogenic belt (Kerman Cenozoic Mamatic Arc, KCMA). This ore deposit is hosted by the Eocene extrusive igneous rocks (tuff, agglomerate, andesite, and dacite) and the Oligo-Miocene intrusive igneous body (granodiorite). These rocks are host the propylitic, phyllic, and silicic alteration zones (product of the mineralization fluids). Hypogene mineralization was dominant and occurs mainly as stockwork vein-veinlets and disseminate (chalcopyrite, pyrite, and magnetite). This mineralization is overprinted by supergene assemblages such as hematite, goethite, malachite, and azurite at superficial part of ore deposit. The hypogene minerals show generally vein-veinlet, stockwork, brecciated, granular, and crustiform textures. Microthermometric studies in quartz crystals cogenetic with the ore minerals reveal 4 types (1) L-V, (2) L-V-S, (3) V-L, and (4) V fluid inclusion. Study of fluid inclusions display a Th range of 190-427ºC. The L-V-S fluid inclusions were homogenized with halite disappearance with the Ts(NaCl) ranging from  213ºC to 425ºC which corresponds with salinities within the range of 32-50 wt% NaCl equivalent. The liquid-rich 2-phase inclusions (L-V) show salinities within the range of 0.6-10 wt% NaCl equivalent. Based on microthermometric data, boiling, mixing, and simple cooling of the ore-bearing fluids were the essential mechanisms in deposition and evolution of this ore deposit. The ore-forming fluids were probably of magmatic and mixed magmatic-meteoric sources. The geological setting, structural and textural aspects, alteration and mineralization of mineral assemblages, as well as microthermometric data show that the Bolboli2 ores can be categorized as porphyry copper-type ore deposit.

The Shalang vein-type polymetallic ore deposit is located about 10 km southwest of Kerman and 70 km northeast of Sirjan, and lies in the central part of the Dehaj-Sarduieh metallogenic belt. This deposit is hosted by dacitic and andesitic vitric and crystal tuffs along with andesitic-dacitic lava flows of Eocene age. The alteration zones related to this deposit are propylitic, intermediate argillic, silicic, and carbonatized. Mineralization occurred principally as veins/veinlets in two separate stages, the hypogene (Chalcopyrite, Pyrite, Magnetite) and the supergene (Bornite, Chalcocite, Malachite, Azurite, & Hematite). The hypogene mineralization also took place in two distinct episodes, (1) formation of quartz-sulfide veins/veinlets and (2) development of carbonate-sulfide veins/veinlets. The average concentration values of cu, Pb, Zn, Au, and Ag within the ore-bearing veins/veinlets are 2.5%, 0.26%, 0.16%, 1.3ppm, and 28ppm, respectively. The strong positive anomaly values of Eu (5.03-10.31) and Ce (1.48-5.06) indicate an alkaline pH and reduced nature, respectively for the ore-forming fluids in the depositional environment. The microthermometric studies on fluid inclusions within the cogenetic quartz crystals were carried out. The studied fluid inclusions were chiefly of liquid-rich two-phase type and all of them were homogenized into liquid state. The obtained homogenization temperatures (Th) of the analyzed fluid inclusions varied within the range of 226º-313ºC. The salinities of the studied fluid inclusions range from 3.4wt% to 9.9 wt% NaCl equivalent. Based upon microthermometric results, the boiling concurrent with cooling were two essential mechanisms in development and evolution of this deposit. Presence of colloform, cockad, blabed, and replacement textures in the ores, development of intermediate argillic and carbonatized alteration zones, and the low salinities and temperatures of the studied fluid inclusions provide persuasive evidence that the Shalang vein-type polymetallic ores have the most similarity to the low-sulfidation epithermal deposits.