نیما نظافتی

The Shadan Porphyry copper-gold ore is located in eastern margin of Tertiary volcano-plutonic belt of the Lut block. Hydrothermal Magmatic solutions of granite-granodiorite stock porphyry rocks that are generally intruded  in the Eocene volcanic rocks resulted  in vast potassic, potassic-phyllic, argillic and propylitic alterations in the area. Mineralization in the Shadan ore has been occurred as porphyry, epithermal-vein and hydrothermal breccia. Mineralization is mostly occurred as scattered, stockworks in granodioritic mass and vein type as sulphide, quartz and carbonate veins, trending northwest-southeast. Mineralization are recognized in two types: oxidized (hematite, magnetite, limonite, goethite)  and sulfide (pyrotite, chalcopyrite ,bornite and covelite). According to microscopic and thermometric studies, genesis of the Shadan copper- gold ore is porphyry-epitermal. The results analysis on the primary ore show that the main metallic minerals in the ore are copper and gold. The EDX spectrum of scanning electron microscopy (SEM) on 53 gold particles shows that gold particles are in the form of native gold and electrum is between 1 and 10 microns in size. The occurrence of gold includes mono gold, trapping gold and intergranular gold. Gold grains are within the limonite, and hematite .

Hesar gold mining area is located in Iran Alborz-Azerbaijan zone. The predominant lithology in the mineral range is volcanic, subvolcanic, and sedimentary rocks of the Cenozoic period, which include volcanic and pyroclastic rocks, andesite-trachyandesite, basalt, eicombrite, and tuffs of the Eocene age and related to the Laramid orogenic phase under the influence of Laramide. Expansion phase of volcanic lava that erupts from several fissures and emerges in the form of delirious dykes and floods and stocks, mainly dacite, rhyodacity with Oligocene age, and alterations related to these masses such as silicification, pyritization and caudal formation Major mineralization in the study area includes pyrite, goethite, magnetite and gold, which is mineralized in two phases and is mainly selective and dispersed. Gold mineralization is the result of the decomposition of pyrite and arsenic pyrite, which is free in the field. The rock has been found to be related to the second phase of volcanic and semi-volcanic outcrops of the Oligomocene age. The results obtained from microscopy studies of fluid shortcuts in quartz mineral indicate that the homogenization temperature varies in the range of 140 to 260 ° C and also the melting temperature of the last ice crystal changes from -0.1 to -9. ° C and salinity is between 0.18 to 14% by weight equivalent of NaCl with a frequency range of 2 to 6% by weight equivalent of NaCl.

The Jizvan region with an area of ​​45 km2 is located about 70 km northwest of Zanjan town in the Tarom-Hashtjin metallogenic zone. The major rock units in the Jizvan area consist of a regular sequence of thin-layered tuff and breccia tuff with intermediate to basic compositions, interlayered with andesites and basalts. In addition, volcanic trachytic and porphyry andesitic rock units are also scattered in the region. Parts of the tuff and breccia tuff sequence are intruded by hypabyssal quartz monzonite, monzodiorite and syenite intrusions in the east of the region. As a result of this event, due to the presence of linear structures and the invasion of hydrothermal fluids, the above-mentioned rocks are affected by advanced argillic alteration. Carbonatic (malachite) and sulfidic (chalcopyrite, bornite, tetrahedrite-tennantite and chalcocite-covellite) copper mineralizations, along with pyrite, galena, sphalerite, arsenopyrite, quartz, calcite and goethite minerals are developed with a vein-veinlet texture in the above-mentioned units. Using the study of primary biphase fluid inclusions containing liquid and gas phases, homogenization temperatures from 95.6 °C to 268.9 °C with the highest frequency at 185 °C are recorded. The salinity of mineralizing fluids is between 4.65 and 23.8 wt% NaCl equivalent, while their density falls in the range from 0.77 to 1.08 g/cm3. Based on the fluid inclusion data, the mixing between magmatic and meteoric waters is the main cause for precipitation of metallic elements and the occurrence of mineralization in Jizvan area. These data overlap with the representative data of epithermal deposits.

Takab-Mahneshan's metallogenic area is essential in gold mineralization, and it is a part of the northern Urmia-Dokhtar magmatic belt. The northern Urmia-Dokhtar has two distinctive features. It contains the Precambrian basement, and the young Mio-Pliocene magmatism rocks overlie its Precambrian basement. Precambrian basement has two different compositions, oceanic and continental crusts (gneiss, granite, mica-schist, greenschist, amphibolite, serpentinite, marble). The Young rocks are composed of hyaloclastite, acidic tuff, andesitic-basaltic, acidic to intermediate intrusions (diorite, granite), limestone, and marl of Qom formation. We categorized the Young rocks into four phases based on their age and positions. The mutual effect of the basement and young magmatism --in the latest phase --creates hydrothermal solutions in the form of a heat engine. The heat engine has caused rotation and variety, increasing mineralization in the area. As a result, there are mines, deposits, gold indications, and some associated gold elements, including Tuzlar, Bayche Bagh, Baghcheh at Mahneshan area, Zarshuran, Agh-darreh, and Ay-Qalesi in Takab. The Tuzlar and Baghcheh deposits with gold mineralization are in a Silicic-argillic zone, including pyrite, gold-bearing silica, argillic and ferrous hydroxides minerals. The Ay-Qalesi polymetallic deposits often contain zinc and lead. The Zarshuran and Agh-darreh deposits are the gold types that the first one has a variety of mineralization of sulfides and sulfosalts. The second one has simple gold mineralization, and finally, the Bayche Bagh deposit with polymetallic type includes chalcopyrite, pyrite, rutile, arsenopyrite, sphalerite, bornite, smaltite, chloanthite, azurite, and malachite minerals.

The studied area in this research is the Esfordi phosphate mine in the Bafq metallogenic state, which apatite, magnetite and hematite are its main mineralization. As one of the high phosphorus iron – apatite mine in the region, this mine contains significant mineralization of rare earth elements with a maximum and average grade of 1.7% and 0.5% (as monazite, zircon and allanite minerals in apatite), and has LREE enrichment and Eu negative anomaly.  In order to primary assessment of REEs concentration status in study area, the outlook coefficient of REEs (Koutl), which is based on the classification of REEs by the level of industry demand, was used. This coefficient is the ratio of the amount of critical REEs (Dy, Tb, Nd, Y, Er and Eu) to the amount of surplus REEs (Ce, Ho, Tm, Yb and Lu), which can be used to investigate mineralization of different types in newly discovered deposits and active mines. The results indicate the highest outlook coefficient (Koutl=0.67) for microgranite to rhyolite with amphibole unit, and also promising average outlook coefficient of 0.53. The Esfordi mine despite the lower grade, it is closer to the ideal composition compared to China's Bayan Obo mine (Koutl=0.2). Thus, can portend a bright future for REEs in this mine, if focus on exploration of these elements and further geochemical and mineralogical investigations are carried out.

The East Chia Sabz site is located at the bank of the Seymareh river in the middle of Zagros Mountain chain. The site is among the few collections of the Acramic Neolithic sites of eighth millenium BCE of Zagros which was archaeologically investigated during the rescue archaeological studies of the Seymareh dam. Numerous bullet-shaped core stones were unearhted during the archaeological excavation of the site, from which some were investigated using XRD analysis. According to the results, most of the lithic artifacts demonstrate a similar mineralogy and it seems that they had been provided from a local source. In this regard, the silisic cobbles of the Amiran Formation that are also available from the river beds could have been a significant source.

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 a systematic multidisciplinary plan for the ancient mining and archaeometallurgical studies of Iran in the future. In this regard, following a brief review of the few systematic researches on the topic in Iran, the problems and challenges concerning the ancient relics of mining and metallurgy have been addressed. The conflict of interests between the modern mining sector and the cultural heritage organization, the lack of systematic plans for the documentation and study of ancient mining and metallurgical studies together with low contribution of the associated private sector in such studies as well as weak analytical infrastructures in the country are among the major challenges of the study of ancient mining and metallurgical relics in Iran. In this respect, an action plan for future studies in different aspects of ancient mining and metallurgy has been proposed. This plan is composed of five major pillars consisting of (1) “Collaboration”: interactive cooperation between associated Iranian institutions including the mining sector and the cultural heritage organization together with international institutions in the frame of the re-establishment of the “committee for studies on old mining and metallurgy”, (2) “Education”: training and education of mining archaeologists and archaeometallurgical experts together with familiarizing geologists, mining engineers, and archaeologists with the subject, (3)”Research”: research and study on the ancient mining and metallurgy by a number of substantial actions including preparation of an archive of the present level of knowledge on the subject which can eventually result in the preparation of an atlas of ancient mining and metallurgical relics of Iran, considering the old questions of archaeology concerning provenance and trade of raw and manufactured materials as well as the exchange of ancient technologies, performing systematic surveys for finding and documentation of the neglected ancient mines and metallurgical sites together with archaeological excavation of the significant ancient mines or metallurgical sites, and boosting the analytical and scientific infrastructure, (4) “Conservation”: preservation and conservation of selected representative ancient mining and metallurgical relics of the mines that are going to be exploited by modern mining sector, and (5) “Presentation”: publication and presentation of the results of the abovementioned aspects in diverse visual forms and appropriate scientific ways not only to the experts but also to the public. In the end, the paper has summarized the priorities concerning the future ancient mining and metallurgical studies of Iran. This road map that has mainly been prepared based on the knowledge and experience of the authors in the public and private sectors of Iran has also benefited from the constructive advices of the prominent international experts including Prentiss de Jesus, Vincent Pigott, Ernst Pernicka, Barbara Helwing, and Thomas Stöllner.