Nima Nezafati

The region of Luristan in the Zagros Mountains (western Iran) is known worldwide for its skilled and enigmatic ancient metal production, in particular its “Luristan Bronzes” dated to the Bronze and Iron Ages. At the crossroads between the IInd and Ist millennia BC, in parallel with tradition of elaborate bronze production, Luristan also saw the arrival of iron. Bimetallic bronze iron artefacts and technically well-developed iron mask swords are among very notable iron products of Luristan metalworkers and are potentially among the oldest iron artefacts known from Iran. Despite this situation, technical aspects of iron metallurgy are almost unknown in Luristan. Field investigations are rare, archaeological production contexts are unknown, and little attention has been paid to iron metalworking. This article, as an initial step in this field, will address the results of a recent short archaeometallurgical survey in Luristan which lead to the discovery of five slag heaps. The physicochemical analyses and microscopic observations, which were carried out at the Departments of Mining Archaeology and Archaeometallurgy of the German Mining Museum, Bochum (DBM), Germany, indicated that we have identified several ironworking workshops: mostly smelting together with some vestiges of smithing activities. In addition, geochemical and isotopic analyses attested that the ores probably came from geochemically similar deposits in the wider region.

This article discusses the impacts of overprinting of tectonic and plutonic events on the mineralization of the Duna Pb-Ba ore deposit, according to geologic settings and fluid inclusion studies. The Duna carbonate-hosted deposit contains a significant amount of Ag (18.9–264.3 ppm ), Cu (77–41600 ppm), Sb (32.7–11000 ppm), Sr (63.5– 15100 ppm), and Fluid inclusions with 7.34–23.65 wt.% NaCl equivalent. The homogenization temperature of about 110–285°C, as well as the paragenesis of the minerals shows a difference compared with other Pb-Zn deposits such as the Irish-type and MVT. The ore mineralization in the Duna mine occurred as stratabound, open space-filling, and along the brecciated fault zones. The concordant (stratabound) type of mineralization, with salinity and homogenization temperature of 18.54 to 23.65 wt.% NaCl equivalent, and 113°C to 165°C respectively, is usually typical of MVT-ore deposits, which in this area evolved during the Early Cimmerian orogeny and was later interrupted by mineralization along younger brecciated fault zones with salinity and homogenization temperature of 7.34 to 23.65 wt.% NaCl equivalent, and 113°C to 285°C respectively. This discordant mineralization, which occurred along the faults, formed by the end of the Late Cretaceous and during the Cenozoic as a result of the intrusion of a plutonic mass, and is comparable to the Irish-type ore deposits.

The present study was conducted to determine different geochemical anomalies of rare-earth elements (REEs) using a combined approach of stepwise factor analysis (SFA), sequential Gaussian simulation (SGS), and concentration–area (C-A) fractal modeling based on surface lithogeochemical samples obtained from the Esfordi phosphate mine (Central Iran). The Esfordi mine is one of the important mines in the Bafq metallogenic zone due to average and maximum grades of 0.5 and 1.7%, respectively for REEs. With SFA operating in two steps, the REEs were placed in the first factor of the second stage (F1-2). Then, SGS and C-A fractal modeling were performed on F1-2 factor scores for classification of anomalies. A log-ratio matrix was used to evaluate the correlation of these results with anomalous lithogeochemical samples, as well as to determine the relationship of anomalies with rock types and mineralized units and, finally, to validate the results of the SGS–fractal modeling. The results confirmed an appropriate correlation between F1-2 anomalies and high concentration in further rock samples. The main anomalies were found to have good correlation with an apatite–iron unit and in general with other apatite-bearing units based on overall accuracy values. The apatite-bearing units with high values of REEs were located in the northern and central parts of the mine. The results of the SFA, SGS and C-A fractal modeling show that this hybrid approach can be useful in determining anomalies with high accuracy.

Ramand mineralization area is located at a distance of about 60 km from the provincial capital of Qazvin province, Iran. The studied area is a part of the Central Iran structural zone in the southern part of Danesfahan geological map. Lithological units in Ramand area are composed of riodacite, rhyolite, tuff riodacite, crystal tuff and riodacite. The presence of clay minerals indicates argillic alteration, which is a good indicator of mineralization. This type of alteration can be detected in volcanic regions which have been severely affected by argillic alteration. Silicification is the most important evidence of precious metal potential in post magmatic environments. According to mineralogical studies, sulfide minerals in the area consist of pyrite and chalcopyrite with supergene minerals such as covellite, malachite, and Fe hydroxides. Based on phase content, the three types of inclusion in Ramand area include vapor, vapor liquid, and liquid rich inclusions. According to fluid inclusion data, the liquid vapor homogenization temperature [T_{H (L–V)}] varied from 73 to 307 °C, and salinity ranged from 1.75 to 4.74 wt% NaCl eq. The calculated δ18O values of water in equilibrium with quartz ranged from 5.8 to 6.9 per ml. Calculated δ18O values of water in equilibrium with calcite ranged from 4.4 to 9.4 per ml. These data suggest that the ores formed most likely originated from magmatic hydrothermal sources along with some meteoric solutions during mineralization processes.

AghBolagh region is located in southwest of West Azarbaijan Province that is 10 km far from north of Oshnavieh. Most of the rocky outcrops in the region include Cambrian deposits (carbonate deposits and clastic deposits (sandstone and shale)). These deposits were later influenced and altered by granite Intrusion. The Intrusion is made of granite and in term of nature, it is magmatic with High-potassium calc-alkaline and peralumin. Also the penetration of intrusion and Ore maker solvent in further distances from the contact point and inside the sequences of sandstone has formed quartzite rocks and ore bearing veins of cooper. The REE pattern normalized to Chondrite for granite, skarn, and marble intrusion and vein deposits shows the fact that, although the REEs pattern is a little smooth and unified, LREEs have more enrichment compared to HREEs in different lithology. The range of normalized numbers to Chondrite in AghBolagh deposit is clearly variable (2.58 to 141.93 for La and 0.14 to 27.27 for Yb). This indicates that there have been clear differences in increase and decrease of LREEs and HREEs during the formation of AghBolagh deposit stones and rocks. The La / Y ratio shows the pH condition of the environment for formation of deposit. This ratio in AghBolagh deposit ranges from 0.09 to 2.26. The granite intrusion shows the most amount of La/Y which is equal to 2. Skarn Zone (Endoskarn and Exoskarn and Ore in Exoskarn) shows two different conditions. The first condition: the part in which LA/Y>1, and this can be observed in samples near the intrusion and Skarn ore is also found in this range. The second condition: the part that La/Y<1, which is near to marble lithology. Also, about vein deposit, the sample is ore making in alkaline conditions, and other samples show acidic conditions. To evaluate the segregation coefficient between REEs, different ratios of REEs including (La/Yb) n ', (La/Sm) n, and (Gd/Yb) n are used. The values of these ratios range from (0.42 to 50.56) for (La/Yb) n; and from (0.25 to 80.125) for (La/Sm) n’; (from 0.006 to 48.8) for (Gd/Yb) n. The highest segregation was between LREEs and HREEs (more than 125) and the least segregation was between MREEs and HREEs during the Skarn process.

Aghbolagh copper deposit is located in the southwest of West Azarbaijan Province, 10 km north of Oshnavieh city. Most of the existing rock outcrops in the area include Cambrian deposits (carbonated and clastic deposits). These deposits are metamorphosed by intrusive-granite masses (skarn-genesis). The infiltration of the mineralization solution at distances beyond contact and inside the sandstone sequences has resulted in the formation of copper ore veins. For microscopic and geochemical studies, 21 thin sections, and 22 doubly-polished cross-sections, 22 XRD specimens, 22 ICP-MS specimens, and three samples for analysis of 10 oxides were analyzed by Zarazma Corporation. In the study of the fluids involved, measurements were made using a Linkham THMSG600 heater and freezer plate, mounted on a polarized microscope with a separate stage and Olympus model. Studies on quartz minerals (3 samples) and garnet minerals (2 samples) were performed on five polished double sections by micro-thermometry measurements on 30 inclusion in quartz mineral and 15 inclusion in garnet mineral at Rizkavan Land Company. The results show that the La/Y ratio, which is a proper indicator for the pH conditions of the formation environment of ore deposit, in Aghbolagh deposit is a range from 0.09 to 2.26. The granite mass has the highest amount, and the skarn zone represents two types of conditions. Type 1: Section where the La/Y> 1 ratio observed in samples close to the skarn mass and ore. Type 2: Part where the ratio La/Y <1 is close to marble lithology. In the case of a vein deposit, the samples have mineralization under alkaline conditions, and other samples show acidic conditions. The examination of fluid inclusions determined two main groups of fluids in this mineralization system. Group 1: Supersaturated fluids of salt, which is the origin of halite multiphase inclusions in the garnet ore during the progressive skarn alteration process. Group 2: Salt-saturated fluids, which are the source of fluid-rich two-phase intermediates in the garnet and quartz minerals, and have been effective in regressive alteration in the skarn system.

The IIC deposit area to the east of the Bafq region exposes rocks that comprise the part of the Central Iran continental terrane. The IIC deposit iron orebodies are magmatic-related hydrothermal deposits that, when considered collectively display a vertical zonation from high-temperature, magmatic ± hydrothermal deposits emplaced at moderate depths (~1–2 km) to magnetite-dominant IOCG deposits emplaced at an even shallower subvolcanic level. The shallowest parts of these systems include near-surface, iron oxide-only replacement deposits, surficial epithermal sediment-hosted replacement deposits, and synsedimentary (exhalative) ironstone deposits. Alteration associated with the IOCG mineralizing system within the host volcanic, plutonic, and sedimentary rocks dominantly produced potassic with lesser amounts of calcic- and sodic-rich mineral assemblages. Our data suggest that hydrothermal magmatic fluids contributed to formation of the primary sodic and calcic alterations. The aim of this study is to delineate and recognize the different iron mineralized zones, based on surface and subsurface study. However, the data do not discriminate between a magmatic-hydrothermal source fluids resolved from Fe-rich immiscible liquid or Fe-rich silicate magma. Iron ores, occurring as massive-type and vein-type bodies are chemically different. Minor pyrite occurs as a late phase in the iron ores. The REE patterns of the mineralized metasomatites show LREE enrichment and strong Eu negative anomalies. The strong negative Eu anomaly probably indicates near-surface fractionation of alkali rhyolites involving feldspars. Field observations, ore mineral and alteration assemblages, coupled with lithogeochemical data suggest that an evolving fluid from magmatic dominated to surficial brine-rich fluid has contributed to the formation of the IIC deposit.

Iran is rich in ancient mining and metallurgical relics. Nevertheless, the studies on these relics have so far been mostly unsystematic. The road map for the ancient mining and metallurgical studies in Iran, that has been ordered by the Research Centre for Conservation of Cultural Relics of Iran (RCCCR), proposes ...

The world heritage ancient site of Takht-e Soleyman and its assemblage of metal objects, together with the geological wealth and the vast ancient mining relics of the Takab area motivated the authors to conduct the investigation that led to this article. The ancient mining and ore processing sites of the Takht-e Soleyman area were surveyed and investigated in an area of 5000 km2. This contribution introduces briefly the geology and mineral resources together with the traces of ancient mining and ore processing in the area of Takht-e Soleyman. Some archaeological sites were found and documented for the first time during this investigation.